Loop over multiple arrays simultaneously: Difference between revisions

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Task

Loop over multiple arrays (or lists or tuples or whatever they're called in your language) and display the i ^th element of each.

Use your language's "for each" loop if it has one, otherwise iterate through the collection in order with some other loop.

For this example, loop over the arrays:

    (a,b,c)
    (A,B,C) 
    (1,2,3)

to produce the output:

    aA1
    bB2
    cC3

If possible, also describe what happens when the arrays are of different lengths.

Related tasks

11l

L(x, y, z) zip(‘abc’, ‘ABC’, ‘123’)
   print(x‘’y‘’z)

Output:

aA1
bB2
cC3

360 Assembly

*        Loop over multiple arrays simultaneously  09/03/2017
LOOPSIM  CSECT
         USING  LOOPSIM,R12        base register
         LR     R12,R15
         LA     R6,1               i=1
         LA     R7,3               counter=3
LOOP     LR     R1,R6              i
         SLA    R1,1               *2
         LH     R2,R-2(R1)         r(i)
         XDECO  R2,PG              edit r(i)
         LA     R1,S-1(R6)         @s(i) 
         MVC    PG+3(1),0(R1)      output s(i)
         LA     R1,Q-1(R6)         @q(i)
         MVC    PG+7(1),0(R1)      output q(i)
         XPRNT  PG,80              print s(i),q(i),r(i)
         LA     R6,1(R6)           i++
         BCT    R7,LOOP            decrement and loop
         BR     R14                exit
S        DC     C'a',C'b',C'c'
Q        DC     C'A',C'B',C'C'
R        DC     H'1',H'2',H'3'
PG       DC     CL80' '            buffer
         YREGS
         END    LOOPSIM

Output:

   a   A   1
   b   B   2
   c   C   3

8080 Assembly

The 8080 has no indexing mechanism at all, so generally one would iterate over arrays by incrementing the pointers in-place rather than do it this way, but it can (just about) be done.

The 8080 has 7 eight-bit registers (A, B, C, D, E, H, L), six of which can form three 16-bit pairs (BC, DE, HL). Of those, HL is special: only it can be used for math, and it can be used as a pointer (the 8-bit pseudo-register M refers to the byte in memory at [HL]). Furthermore, the contents of DE and HL can be swapped, so a secondary pointer can be kept in DE and easily accessed. However, this cannot be done with BC.

Therefore, this code keeps the index in BC, and the list of arrays in DE. Array access is done by loading the array pointers into HL one by one, calculating the address by adding BC to it, then loading the appropriate value.

This code simply assumes that the arrays are all the same size (Alen), and if they are not, it will simply read from the wrong addresses.

	org	100h
	lxi	b,0	; Let (B)C be the array index
outer:	lxi	d,As	; Use DE to walk the array-of-arrays
inner:	xchg		; Swap DE and HL (array-of-array pointer into HL)
	mov	e,m	; Load low byte of array pointer into E
	inx	h
	mov	d,m	; Load high byte of array pointer into D 
	inx	h
	xchg		; Array base in HL, array-of-array pointer in DE
	mov	a,h	; Is HL 0?
	ora	l
	jz	azero	; If so, we are done.
	dad	b	; Otherwise, add index to array base
	mov	a,m	; Get current item (BC'th item of HL)
	call	chout	; Output
	jmp	inner	; Next array 
azero:	mvi	a,13	; Print newline	
	call	chout
	mvi	a,10
	call	chout
	inr	c	; Increment index (we're only using the low byte)
	mvi	a,Alen	; Is it equal to the length?
	cmp	c
	jnz	outer	; If not, get next item from all the arrays.
	ret		
	;;;	Print character in A, saving all registers.
	;;;	This code uses CP/M to do it.
chout:	push 	psw	; CP/M destroys all registers
	push	b	; Push them all to the stack
	push	d
	push	h
	mvi	c,2	; 2 = print character syscall
	mov	e,a
	call	5
	pop	h	; Restore registers
	pop	d
	pop	b
	pop	psw
	ret
	;;;	Arrays
A1:	db	'a','b','c'
A2:	db	'A','B','C'
A3:	db	'1','2','3'
Alen:	equ	$-A3
	;;;	Zero-terminated array-of-arrays
As:	dw	A1,A2,A3,0

Output:

aA1
bB2
cC3

8086 Assembly

The 8086 processor has two index registers si and di, and an address register bx. (There is also the base pointer bp, which is used to point to the stack segment, and is not used here.)

When addressing memory, the 8086 can automatically add up: 1) one of bx or bp, plus 2) one of si or di, plus 3) a direct address.

This code uses si to keep track of the current index, and loads the base addresses of the arrays into bx one by one.

	cpu	8086
	bits	16
	org	100h
section	.text
	mov	ah,2		; Tell MS-DOS to print characters
	xor	si,si		; Clear first index register (holds _i_)	
outer:	mov	di,As		; Put array-of-arrays in second index register
	mov	cx,Aslen	; Put length in counter register
inner:	mov	bx,[di]		; Load array pointer into BX (address) register
	mov	dl,[bx+si]	; Get SI'th element from array
	int	21h		; Print character
	inc	di		; Go to next array (pointers are 2 bytes wide)
	inc	di
	loop	inner		; For each array
	mov	dl,13		; Print newline
	int	21h
	mov	dl,10
	int	21h
	inc	si		; Increment index register
	cmp	si,Alen		; If it is still lower than the array length
	jb	outer		; Print the next items
	ret
section	.data
	;;;	Arrays
A1:	db	'a','b','c'
A2:	db 	'A','B','C'
A3:	db	'1','2','3'
Alen:	equ	$-A3		; Length of arrays (elements are bytes)
	;;;	Array of arrays
As:	dw	A1,A2,A3
Aslen:	equ	($-As)/2	; Length of array of arrays (in words)

Output:

aA1
bB2
cC3

ACL2

(defun print-lists (xs ys zs)
   (if (or (endp xs) (endp ys) (endp zs))
       nil
       (progn$ (cw (first xs))
               (cw "~x0~x1~%"
                   (first ys)
                   (first zs))
               (print-lists (rest xs)
                            (rest ys)
                            (rest zs)))))

(print-lists '("a" "b" "c") '(A B C) '(1 2 3))

Action!

PROC Main()
  CHAR ARRAY a="abc",b="ABC"
  BYTE ARRAY c=[1 2 3]
  BYTE i

  FOR i=0 TO 2
  DO
    PrintF("%C%C%B%E",a(i+1),b(i+1),c(i))
  OD
RETURN

Output:

Screenshot from Atari 8-bit computer

aA1
bB2
cC3

Ada

with Ada.Text_IO;  use Ada.Text_IO;

procedure Array_Loop_Test is
   type Array_Index is range 1..3;
   A1 : array (Array_Index) of Character := "abc";
   A2 : array (Array_Index) of Character := "ABC";
   A3 : array (Array_Index) of Integer   := (1, 2, 3);
begin
   for Index in Array_Index'Range loop
      Put_Line (A1 (Index) & A2 (Index) & Integer'Image (A3 
(Index))(2));
   end loop;
end Array_Loop_Test;

ALGOL 68

Works with: ALGOL 68 version Revision 1 - no extensions to language used

Works with: ALGOL 68G version Any - tested with release

[http://sourceforge.net/projects/algol68/files/algol68g/algol68g-1.18.0/algol68g-1.18.0-9h.tiny.el5.centos.fc11.i386.rpm/download

1.18.0-9h.tiny]

[]UNION(CHAR,INT) x=("a","b","c"), y=("A","B","C"), 
z=(1,2,3);
FOR i TO UPB x DO
  printf(($ggd$, x[i], y[i], z[i], $l$))
OD

Output:

aA1
bB2
cC3

ALGOL W

begin
    % declare the three arrays                                               %
    string(1) array a, b ( 1 :: 3 );
    integer   array c    ( 1 :: 3 );
    % initialise the arrays - have to do this element by element in Algol W  %
    a(1) := "a"; a(2) := "b"; a(3) := "c";
    b(1) := "A"; b(2) := "B"; b(3) := "C";
    c(1) :=  1;  c(2) :=  2;  c(3) :=  3;
    % loop over the arrays                                                   %
    for i := 1 until 3 do write( i_w := 1, s_w := 0, a(i), b(i), c(i) );
end.

If the arrays are not the same length, a subscript range error would occur when a non-existant element was accessed.

Amazing Hopper

Versión 1: todos los arrays tienen el mismo tamaño:

#include <jambo.h>

Main
   Void 'x,y,z'
   Set '"a","b","c"' Append to list 'x'
   Set '"A","B","C"' Append to list 'y'
   Set '1,2,3'       Append to list 'z'
   i=1
   Loop
       [i++], Printnl ( Get 'x', Get 'y', Get 'z' )
   Back if less-equal (i, 3)
End

Output:

aA1
bB2
cC3

Versión 2: los arrays tienen distinto tamaño:

#include <jambo.h>

Main
   Void 'x,y,z'
   Let list ( x := "a","b","c" )
   Let list ( y := "A","B","C","D","E" )
   Let list ( z := 1,2,3,4 )
   i=1, error=0
   Loop
       [i++]
       Try ; Get 'x', Print it ; Catch 'error'; Print (" ") ; Finish
       Try ; Get 'y', Print it ; Catch 'error'; Print (" ") ; Finish
       Try ; Get 'z', Print it ; Catch 'error'; Print (" ") ; Finish
       Prnl
   Back if less-equal (i, 5)
End

Output:

aA1
bB2
cC3
 D4
 E

APL

In APL, one would not use an explicit loop for this. Rather, there is a built-in function to turn a vector of vectors into a matrix, which is ↑. The matrix can be transposed (⍉), and then turned back into a nested vector (↓). The elements could be processed linearly afterwards.

If the input vectors are not all the same size, the shorter vectors will be padded with empty values (spaces for character vectors, zeroes for numeric vectors) to match the longest vector.

f ← ↓∘⍉∘↑

Output:

      f 'abc' 'ABC' '123'
┌───┬───┬───┐
│aA1│bB2│cC3│
└───┴───┴───┘

AppleScript

Translation of: JavaScript

(Functional ES 5 zipListsWith version)

If we have a generic Applescript map function, we can use it to write a generic zipListsWith, which applies a given function over lists derived from the nth members of an arbitrary list of (equal-length) lists. (Where lists are of uneven length, items beyond the maximum shared length are ignored).

-- ZIP LISTS WITH FUNCTION ---------------------------------------------------

-- zipListsWith :: ([a] -> b) -> [[a]] -> [[b]]
on zipListsWith(f, xss)
    set n to length of xss
    
    script
        on |λ|(_, i)
            script
                on |λ|(xs)
                    item i of xs
                end |λ|
            end script
            
            if i ≤ n then
                apply(f, (map(result, xss)))
            else
                {}
            end if
        end |λ|
    end script
    
    if n > 0 then
        map(result, item 1 of xss)
    else
        []
    end if
end zipListsWith


-- TEST  ( zip lists with concat ) -------------------------------------------
on run
    
    intercalate(linefeed, ¬
        zipListsWith(concat, ¬
            [["a", "b", "c"], ["A", "B", "C"], [1, 2, 3]]))
    
end run


-- GENERIC FUNCTIONS ---------------------------------------------------------

-- apply (a -> b) -> a -> b
on apply(f, a)
    mReturn(f)'s |λ|(a)
end apply

-- concat :: [[a]] -> [a] | [String] -> String
on concat(xs)
    if length of xs > 0 and class of (item 1 of xs) is string then
        set acc to ""
    else
        set acc to {}
    end if
    repeat with i from 1 to length of xs
        set acc to acc & item i of xs
    end repeat
    acc
end concat

-- intercalate :: Text -> [Text] -> Text
on intercalate(strText, lstText)
    set {dlm, my text item delimiters} to {my text item delimiters, strText}
    set strJoined to lstText as text
    set my text item delimiters to dlm
    return strJoined
end intercalate

-- map :: (a -> b) -> [a] -> [b]
on map(f, xs)
    tell mReturn(f)
        set lng to length of xs
        set lst to {}
        repeat with i from 1 to lng
            set end of lst to |λ|(item i of xs, i, xs)
        end repeat
        return lst
    end tell
end map

-- Lift 2nd class handler function into 1st class script wrapper 
-- mReturn :: Handler -> Script
on mReturn(f)
    if class of f is script then
        f
    else
        script
            property |λ| : f
        end script
    end if
end mReturn

Output:

aA1
bB2
cC3

But a transpose function might be simpler:

-- CONCAT MAPPED OVER A TRANSPOSITION ----------------------------------------
on run
    
    unlines(map(concat, transpose([["a", "b", "c"], ["A", "B", "C"], [1, 2, 3]])))
    
end run

-- GENERIC FUNCTIONS ---------------------------------------------------------

-- concat :: [[a]] -> [a] | [String] -> String
on concat(xs)
    if length of xs > 0 and class of (item 1 of xs) is string then
        set acc to ""
    else
        set acc to {}
    end if
    repeat with i from 1 to length of xs
        set acc to acc & item i of xs
    end repeat
    acc
end concat

-- intercalate :: String -> [String] -> String
on intercalate(s, xs)
    set {dlm, my text item delimiters} to {my text item delimiters, s}
    set str to xs as text
    set my text item delimiters to dlm
    return str
end intercalate

-- map :: (a -> b) -> [a] -> [b]
on map(f, xs)
    tell mReturn(f)
        set lng to length of xs
        set lst to {}
        repeat with i from 1 to lng
            set end of lst to |λ|(item i of xs, i, xs)
        end repeat
        return lst
    end tell
end map

-- Lift 2nd class handler function into 1st class script wrapper 
-- mReturn :: Handler -> Script
on mReturn(f)
    if class of f is script then
        f
    else
        script
            property |λ| : f
        end script
    end if
end mReturn

-- transpose :: [[a]] -> [[a]]
on transpose(xss)
    script column
        on |λ|(_, iCol)
            script row
                on |λ|(xs)
                    item iCol of xs
                end |λ|
            end script
            
            map(row, xss)
        end |λ|
    end script
    
    map(column, item 1 of xss)
end transpose

-- unlines :: [String] -> String
on unlines(xs)
    intercalate(linefeed, xs)
end unlines

Output:

aA1
bB2
cC3

Arturo

parts: ["abc" "ABC" [1 2 3]]

loop 0..2 'x -> 
    print ~"|parts\0\[x]||parts\1\[x]||parts\2\[x]|"

Output:

aA1
bB2
cC3

AutoHotkey

Pseudo-arrays

StringSplit creates a pseudo-array

List1 = a,b,c
List2 = A,B,C
List3 = 1,2,3
MsgBox, % LoopMultiArrays()

List1 = a,b,c,d,e
List2 = A,B,C,D
List3 = 1,2,3
MsgBox, % LoopMultiArrays()


;---------------------------------------------------------------------------
LoopMultiArrays()

 { ; print the ith element of each
;---------------------------------------------------------------------------


    local Result
    StringSplit, List1_, List1, `,
    StringSplit, List2_, List2, `,
    StringSplit, List3_, List3, `,
    Loop, % List1_0
        Result .= List1_%A_Index% List2_%A_Index% List3_%A_Index% "`n"
    Return, Result
}

An array that is too short on creation will return empty strings when trying to retrieve further elements. The 2nd Message box shows:

aA1
bB2
cC3
dD
e

Real arrays

Works with: AutoHotkey_L

In AutoHotkey_L, we can use true arrays (Objects) and the For loop.

List1 := ["a", "b", "c"]
List2 := ["A", "B", "C"]
List3 := [ 1 ,  2 ,  3 ]
MsgBox, % LoopMultiArrays()

List1 := ["a", "b", "c", "d", "e"]
List2 := ["A", "B", "C", "D"]
List3 := [1,2,3]
MsgBox, % LoopMultiArrays()


LoopMultiArrays() {
    local Result
    For key, value in List1
        Result .= value . List2[key] . List3[key] "`n"
    Return, Result
}

The output from this script is identical to the first one.

AWK

BEGIN {
  split("a,b,c", a, ",");
  split("A,B,C", b, ",");
  split("1,2,3", c, ",");

  for(i = 1; i <= length(a); i++) {
    print a[i] b[i] c[i];
  }
}

Axe

Note that in this example, we use a few bytes from each of L₁, L₂, and L₃ for simplicity. In practice, one would want to arrange the arrays to all fit within L₁ to avoid volatility issues with L₂ and L₃.

'a'→{L₁}
'b'→{L₁+1}
'c'→{L₁+2}
'A'→{L₂}
'B'→{L₂+1}
'C'→{L₂+2}
1→{L₃}
2→{L₃+1}
3→{L₃+2}
For(I,0,2)
Disp {L₁+I}►Char,{L₂+I}►Char,{L₃+I}►Dec,i
End

Babel

There are two ways to do this in Babel. First, you could transpose the lists:

main: { (('a' 'b' 'c')('A' 'B' 'C')('1' '2' '3')) 
simul_array }

simul_array!:
    { trans
    { { << } each "\n" << } each }

The 'trans' operator substitutes nil in the portions of each transposed column wherever a row list was shorter than the longest row list. The '<<' operator prints nothing if the top-of-stack is nil.

A more literal solution to the problem as presented would be to iterate across each list using a user-defined cdrall operator:

main: { (('a' 'b' 'c')('A' 'B' 'C')('1' '2' '3')) 
simul_array }

simul_array!: 
    {{ dup 
        { car << } each 
        cdrall }
        { allnil? not }
    while }

cdrall!: { { { cdr } each -1 take } nest }

-- only returns true if all elements of a list are nil
allnil?!: 
    { 1 <->
    { car nil? 
        { zap 0 last }
        { nil }
    if} each }

This solution is formally identical to the first and will handle lists of varying lengths by printing inserting nil and printing nothing for the tail ends

of the

short lists.

BASIC

Applesoft BASIC

Translation of: ZX Spectrum Basic

REM DEFINE THE ARRAYS AND POPULATE THEM
 0 SIZE = 3: DIM A$(SIZE),B$(SIZE),C(SIZE): FOR I = 1 TO SIZE:A$(I) =  CHR$ (96 + I):B$(I) =  CHR$ (64 + I):C(I) = I: NEXT

REM LOOP OVER MULTIPLE ARRAYS SIMULTANEOUSLY
 1  FOR I = 1 TO SIZE
 2      PRINT A$(I)B$(I)C(I)
 3  NEXT I

BaCon

DECLARE a1$[] = {"a", "b", "c"} TYPE STRING 
DECLARE a2$[] = {"A", "B", "C"} TYPE STRING 
DECLARE a3[] = {1, 2, 3} TYPE int
 

	WHILE (a3[i] <= 3) 
		PRINT  a1$[i], a2$[i], a3[i]
		INCR i
	WEND

BASIC256

arraybase 1
dim arr1$(3) : arr1$ = {"a", "b", "c"}
dim arr2$(3) : arr2$ = {"A", "B", "C"}
dim arr3(3)  : arr3 = {1, 2, 3}

for i = 1 to 3
	print arr1$[i]; arr2$[i]; arr3[i]
next i
print

# For arrays of different lengths we would need to iterate up to the mimimm 
# length of all 3 in order to  get a contribution from each one. For example:

dim arr4$(4) : arr4$ = {"A", "B", "C", "D"}
dim arr5(2)  : arr5 = {1, 2}

ub = min(arr1$[?], min((arr4$[?]), (arr5[?])))
for i = 1 To ub
	print arr1$[i]; arr4$[i]; arr5[i]
next i
print
end

function min(x,y)
	if(x < y) then return x else return y
end function

Output:

Same as FreeBASIC entry.

BBC BASIC

      DIM array1$(2), array2$(2), array3%(2)
      array1$() = "a", "b", "c"
      array2$() = "A", "B", "C"
      array3%() = 1, 2, 3
      
      FOR index% = 0 TO 2
        PRINT array1$(index%) ; array2$(index%) ; array3%(index%)
      NEXT

FreeBASIC

' FB 1.05.0 Win64

Function min(x As Integer, y As Integer) As Integer
  Return IIf(x < y, x, y)
End Function

Dim arr1(1 To 3) As String = {"a", "b", "c"}
Dim arr2(1 To 3) As String = {"A", "B", "C"}
Dim arr3(1 To 3) As Integer = {1, 2, 3}

For i As Integer = 1 To 3
  Print arr1(i) & arr2(i) & arr3(i)
Next

Print

' For arrays of different lengths we would need to iterate up to the mimimm length of all 3 in order
' to  get a contribution from each one. For example:

Dim arr4(1 To 4) As String = {"A", "B", "C", "D"}
Dim arr5(1 To 2) As Integer = {1, 2}

Dim ub As Integer = min(UBound(arr1), min(UBound(arr4), UBound(arr5)))
For i As Integer = 1 To ub
  Print arr1(i) & arr2(i) & arr3(i)
Next

Print
Sleep

Output:

aA1
bB2
cC3

aA1
bB2

Gambas

Click this link to run this code

Public Sub Main()
Dim a1 As String[] = ["a", "b", "c"]
Dim a2 As String[] = ["A", "B", "C"]
Dim a3 As String[] = ["1", "2", "3"]
Dim siC As Short

For siC = 0 To a1.Max
  Print a1[siC] & a2[siC] & a3[siC]
Next

End

Output:

aA1
bB2
cC3

Liberty BASIC

a$(1)="a" : a$(2)="b" : a$(3)="c"
b$(1)="A" : b$(2)="B" : b$(3)="C"
c(1)=1 : c(2)=2 : c(3)=3


for i = 1 to 3
    print a$(i);b$(i);c(i)
next

NS-HUBASIC

10 DIM A$(3)
20 DIM B$(3)
30 DIM C$(3)
40 A$(1)="THIS"
50 A$(2)=" LOOPS"
60 A$(3)=" ARRAYS"
70 B$(1)=" NS-HUBASIC"
80 B$(2)=" OVER"
90 B$(3)=" AT"
100 C$(1)=" PROGRAM"
110 C$(2)=" MULTIPLE"
120 C$(3)=" ONCE."
130 FOR I=1 TO 3
140 PRINT A$(I)B$(I)C$(I)
150 NEXT

PowerBASIC

FUNCTION PBMAIN () AS LONG
    DIM x(2), y(2) AS STRING * 1
    DIM z(2) AS LONG

    'data
    ARRAY ASSIGN x() = ("a", "b", "c")
    ARRAY ASSIGN y() = ("A", "B", "C")
    ARRAY ASSIGN z() = (1, 2, 3)

    'set upper bound
    C& = UBOUND(x)
    IF UBOUND(y) > C& THEN C& = UBOUND(y)
    IF UBOUND(z) > C& THEN C& = UBOUND(z)

    OPEN "output.txt" FOR OUTPUT AS 1
    FOR L& = 0 TO C&
        IF L& <= UBOUND(x) THEN PRINT #1, x(L&);
        IF L& <= UBOUND(y) THEN PRINT #1, y(L&);
        IF L& <= UBOUND(z) THEN PRINT #1, TRIM$(STR$(z(L&)));
        PRINT #1,
    NEXT
    CLOSE
END FUNCTION

PureBasic

OpenConsole()
; Fill arrays
Dim a.s(2)
Dim b.s(2)
Dim c(2)
For Arrayposition = 0 To ArraySize(a())
  a(Arrayposition) = Chr(Asc("a") + Arrayposition)
  b(Arrayposition) = Chr(Asc("A") + Arrayposition)
  c(Arrayposition) = Arrayposition + 1
Next
; loop over them
For Arrayposition = 0 To ArraySize(a())
  PrintN(a(Arrayposition) + b(Arrayposition) + Str(c(Arrayposition)))
Next
Input() ;wait for Enter before ending

If they have different lengths there are two cases:
a() is the shortest one: Only elements up to maximum index of a() are printed
a() is bigger than another one: if exceeding index to much, program crashes,
else it may work because there is some "free space" after end of assigned array memory.
For example if a has size 4, line dD4 will also be printed. size 20 leads to an crash
This is because ReDim becomes slow if everytime there is a change to array size new memory has to be allocated.

Run BASIC

for i = 1 to 3
 a$(i) = chr$(i+96)
 b$(i) = chr$(i+64)
 c(i)  = i
next i 

for i = 1 to 3
    print a$(i);b$(i);c(i)
next

Visual Basic .NET

Two implementations: one determines the shortest of the arrays and uses a simple For loop with element accesses to each array separately; one uses Enumerable.Zip (which can only zip two sequences at once) twice to create 3-tuples. Enumerable.Zip stops when either source runs out of elements, so the behavior of the two implementations is identical for arrays of different lengths.

Module Program
    Sub Main()
        Dim a As Char() = {"a"c, "b"c, "c"c}
        Dim b As Char() = {"A"c, "B"c, "C"c}
        Dim c As Integer() = {1, 2, 3}

        Dim minLength = {a.Length, b.Length, c.Length}.Min()
        For i = 0 To minLength - 1
            Console.WriteLine(a(i) & b(i) & c(i))
        Next

        Console.WriteLine()

        For Each el As (a As Char, b As Char, c As Integer) In a.Zip(b, Function(l, r) (l, r)).Zip(c, Function(x, r) (x.l, x.r, r))
            Console.WriteLine(el.a & el.b & el.c)
        Next
    End Sub
End Module

Output:

aA1
bB2
cC3

aA1
bB2
cC3

XBasic

Works with: Windows XBasic

' Loop over multiple arrays simultaneously
PROGRAM "loopoverarrays"

DECLARE FUNCTION Entry()

FUNCTION Entry()
  DIM arr1$[2], arr2$[2], arr3%[2]
  arr1$[0] = "a": arr1$[1] = "b": arr1$[2] = "c"
  arr2$[0] = "A": arr2$[1] = "B": arr2$[2] = "C"
  arr3%[0] = 1:   arr3%[1] = 2:   arr3%[2] = 3
  FOR i% = 0 TO 2
    PRINT arr1$[i%]; arr2$[i%]; FORMAT$("#", arr3%[i%])
  NEXT i%
END FUNCTION
END PROGRAM

Yabasic

dim arr1$(3), arr2$(3), arr3(3)
arr1$(1) = "a"
arr1$(2) = "b"
arr1$(3) = "c"
arr2$(1) = "A"
arr2$(2) = "B"
arr2$(3) = "C"
arr3(1) = 1
arr3(2) = 2
arr3(3) = 3

for i = 1 to 3
    print arr1$(i), arr2$(i), arr3(i)
next
print

// For arrays of different lengths we would need to iterate up to the mimimm 
// length of all 3 in order to  get a contribution from each one. For example:

dim arr4$(4), arr5(2)
arr4$(1) = "A"
arr4$(2) = "B"
arr4$(3) = "C"
arr4$(4) = "D"
arr5(1) = 1
arr5(2) = 2

ub = min(arraysize(arr1$(),1), min(arraysize(arr4$(),1),arraysize(arr5(),1)))
for i = 1 to ub
    print arr1$(i), arr4$(i), arr5(i)
next
end

Output:

Same as FreeBASIC entry.

ZX Spectrum Basic

10 LET sza = 3: REM size of a
20 LET szb = 3: REM size of b
30 LET szc = 3: REM size of c
40 DIM a$(sza): DIM b$(szb): DIM c$(szc)
50 LET max = sza: REM assume a is the biggest
60 IF szb > max THEN LET max = szb: REM now try b
70 IF szc > max THEN LET max = szc: REM or c
80 REM populate our arrays, and as a bonus we already have our demo loop
90 REM we might as well print as we populate showing the arrays in 
columns
100 FOR l = 1 TO max
110 IF l <= sza THEN READ a$(l): PRINT a$(l);
120 IF l <= szb THEN READ b$(l): PRINT b$(l);
130 IF l <= szc THEN READ c$(l): PRINT c$(l);
140 PRINT: REM newline
145 NEXT l
150 PRINT "The arrays are shown in columns."
160 PRINT "A$ runs down the left hand side,"
170 PRINT "and C$ runs down the right."
180 STOP
200 DATA "a","b","c","A","B","C","1","2","3"

Simplification

10 READ size: DIM a$(size): DIM b$(size): DIM c$(size)
20 FOR i=1 TO size
30 READ a$(i),b$(i),c$(i)
40 PRINT a$(i);b$(i);c$(i)
50 NEXT i
60 DATA 3,"a","A","1","b","B","2","c","C","3"

Beads

This solution accounts for arrays of varying lengths, and if they are interspersed with undefined characters by replacing them with spaces.

beads 1 program 'Loop over multiple arrays simultaneously'
calc main_init
	const 
		x = ['a', 'b', 'c']
		y = ['A', 'B', 'C']
		z = [1, 2, 3]
	const largest = max(tree_hi(x), tree_hi(y), tree_hi(z))
	loop reps:largest count:i    //where u_cc defines what to use for undefined characters
		log to_str(x[i], u_cc:' ') & to_str(y[i], u_cc:' ') & to_str(z[i], u_cc:' ')

Output:

aA1
bB2
cC3

Befunge

There's no concept of an array data type in Befunge, but you'd typically store your arrays as sequences of data in the Befunge code space. You'd then loop over the range of indices required to access those arrays, and use the loop variable as an offset into each data area. For arrays of differing lengths, you'd need to manually check for an out-of-range index and deal with it appropriately.

0 >:2g,:3g,:4gv
@_^#`2:+1,+55,<
abc
ABC
123

C

Given several arrays, especially if they are heterogeneous, the most ordinary way to loop over all of them is to simply use an index variable. Determining when to stop is generally done in some application-specific way.

#include <stdio.h>

char a1[] = {'a','b','c'};
char a2[] = {'A','B','C'};
int a3[] = {1,2,3};

int main(void) {
    for (int i = 0; i < 3; i++) {
        printf("%c%c%i\n", a1[i], a2[i], a3[i]);
    }
}

(Note: Some compilers may require a flag to accept this modern C code, such as gcc -std=c99.)

On the other hand, it is possible to write a more generic higher-order iteration scheme, as demonstrated in this example.

There, a type for arrays with runtime-specified lengths and polymorphic
printing is defined, and the iteration continues up to the length of

the shortest array.

C#

class Program
{
    static void Main(string[] args)
    {
        char[] a = { 'a', 'b', 'c' };
        char[] b = { 'A', 'B', 'C' };
        int[] c = { 1, 2, 3 };
        int min = Math.Min(a.Length, b.Length);
        min = Math.Min(min, c.Length);
        for (int i = 0; i < min; i++)
            Console.WriteLine("{0}{1}{2}", a[i], b[i], c[i]);
    }             
}

Using Enumerable.Zip (stops when either source runs out of elements):

int[] numbers = { 1, 2, 3, 4 };
string[] words = { "one", "two", "three" };
Console.WriteLine(numbers.Zip(words, (first, second) => first + " " +
 second));

Like how a perl programmer would write it (still using Zip):

Console.WriteLine((new[] { 1, 2, 3, 4 }).Zip(new[] { "a", "b", "c" }, 
(f, s) => f + " " + s));

Custom implementation for arrays of different lengths that pads with spaces after the end of the shorter arrays:

        public static void Multiloop(char[] A, char[] B, int[] C)
        {
            var max = Math.Max(Math.Max(A.Length, B.Length), C.Length);
            for (int i = 0; i < max; i++)
               Console.WriteLine($"{(i < A.Length ? A[i] : ' ')}, {(i < B.Length ? B[i] : ' ')}, {(i < C.Length ? C[i] : ' ')}");
        }

usage:

Multiloop(new char[] { 'a', 'b', 'c', 'd' }, new char[] { 'A', 'B', 'C' }, new int[] { 1, 2, 3, 4, 5 });

C++

With std::vectors:

#include <iostream>
#include <vector>

int main(int argc, char* argv[])
{
   std::vector<char> ls(3); ls[0] = 'a'; ls[1] = 'b'; ls[2] = 'c';
   std::vector<char> us(3); us[0] = 'A'; us[1] = 'B'; us[2] = 'C';
   std::vector<int> ns(3);  ns[0] = 1;   ns[1] = 2;   ns[2] = 3;

   std::vector<char>::const_iterator lIt = ls.begin();
   std::vector<char>::const_iterator uIt = us.begin();
   std::vector<int>::const_iterator nIt = ns.begin();
   for(; lIt != ls.end() && uIt != us.end() && nIt != 
ns.end();
       ++lIt, ++uIt, ++nIt)
   {
      std::cout << *lIt << *uIt << *nIt << "\n";
   }
}

Using static arrays:

#include <iostream>

int main(int argc, char* argv[])
{
   char ls[] = {'a', 'b', 'c'};
   char us[] = {'A', 'B', 'C'};
   int ns[] = {1, 2, 3};

   for(size_t li = 0, ui = 0, ni = 0;
       li < sizeof(ls) && ui < sizeof(us) && ni 
< sizeof(ns) / sizeof(int);
       ++li, ++ui, ++ni)
   {
      std::cout << ls[li] << us[ui] << ns[ni] <<
 "\n";
   }
}

C++11

With std::vectors:

#include <iostream>
#include <vector>

int main(int argc, char* argv[])
{
    auto lowers = std::vector<char>({'a', 'b', 'c'});
    auto uppers = std::vector<char>({'A', 'B', 'C'});
    auto nums = std::vector<int>({1, 2, 3});

    auto ilow = lowers.cbegin();
    auto iup = uppers.cbegin();
    auto inum = nums.cbegin();

    for(; ilow != lowers.end() 
        and iup != uppers.end() 
        and inum != nums.end()
        ; ++ilow, ++iup, ++inum)
    {
       std::cout << *ilow << *iup << *inum << "\n";
    }
}

Using static arrays:

#include <iostream>
#include <iterator>

int main(int argc, char* argv[])
{
    char lowers[] = {'a', 'b', 'c'};
    char uppers[] = {'A', 'B', 'C'};
    int nums[] = {1, 2, 3};

    auto ilow = std::begin(lowers);
    auto iup = std::begin(uppers);
    auto inum = std::begin(nums);

    for(; ilow != std::end(lowers)
        and iup != std::end(uppers)
        and inum != std::end(nums)
        ; ++ilow, ++iup, ++inum )
    {
       std::cout << *ilow << *iup << *inum << "\n";
    }
}

With std::arrays:

#include <iostream>
#include <array>

int main(int argc, char* argv[])
{
    auto lowers = std::array<char, 3>({'a', 'b', 'c'});
    auto uppers = std::array<char, 3>({'A', 'B', 'C'});
    auto nums = std::array<int, 3>({1, 2, 3});

    auto ilow = lowers.cbegin();
    auto iup = uppers.cbegin();
    auto inum = nums.cbegin();

    for(; ilow != lowers.end()
        and iup != uppers.end()
        and inum != nums.end()
        ; ++ilow, ++iup, ++inum )
    {
       std::cout << *ilow << *iup << *inum << "\n";
    }
}

With std::arrays by indexes:

#include <iostream>
#include <array>
#include <algorithm>

int main(int argc, char* argv[])
{
    auto lowers = std::array<char, 3>({'a', 'b', 'c'});
    auto uppers = std::array<char, 3>({'A', 'B', 'C'});
    auto nums = std::array<int, 3>({1, 2, 3});

    auto const minsize = std::min(
                lowers.size(),
                std::min(
                    uppers.size(), 
                    nums.size()
                    )
                );

    for(size_t i = 0; i < minsize; ++i)
    {
       std::cout << lowers[i] << uppers[i] << nums[i] << "\n";
    }
}

C++23

#include <array>
#include <ranges>
#include <format>
#include <iostream>
 
int main() {
    auto a1 = std::array{"a", "b", "c"};
    auto a2 = std::array{"A", "B", "C"};
    auto a3 = std::array{1, 2, 3};

    for(const auto& [x, y, z] : std::ranges::views::zip(a1, a2, a3))
    {
        std::cout << std::format("{}{}{}\n", x, y, z);
    }
}

Chapel

var a1 = [ "a", "b", "c" ];
var a2 = [ "A", "B", "C" ];
var a3 = [  1,   2,   3  ];

for (x,y,z) in zip(a1, a2, a3) do
    writeln(x,y,z);

Clojure

(doseq [s (map #(str %1 %2 %3) "abc" "ABC" "123")] 
  (println s))

The sequence stops when the shortest list is exhausted.

(apply map str ["abc" "ABC" "123"])
("aA1" "bB2" "cC3")

COBOL

       IDENTIFICATION DIVISION.
       PROGRAM-ID. Loop-Over-Multiple-Tables.

       DATA DIVISION.
       WORKING-STORAGE SECTION.
       01  A VALUE "abc".
           03  A-Vals PIC X OCCURS 3 TIMES.

       01  B VALUE "ABC".
           03  B-Vals PIC X OCCURS 3 TIMES.

       01  C VALUE "123".
           03  C-Vals PIC 9 OCCURS 3 TIMES.

       01  I PIC 9.

       PROCEDURE DIVISION.
           PERFORM VARYING I FROM 1 BY 1 UNTIL 3 < I
               DISPLAY A-Vals (I) B-Vals (I) C-Vals (I)
           END-PERFORM

           GOBACK
           .

Common Lisp

Using functional application

(mapc (lambda (&rest args)
        (format t "~{~A~}~%" args))
      '(|a| |b| |c|)
      '(a b c)
      '(1 2 3))

If lists are different lengths, it stops after the shortest one.

Using LOOP

  (loop for x in '("a" "b" "c")
        for y in '(a b c)
        for z in '(1 2 3)
        do (format t "~a~a~a~%" x y z))

Using DO

(do ((x '("a" "b" "c") (rest x))                       ;
     (y '("A" "B" "C" "D") (rest y))                   ;
     (z '(1 2 3 4 6) (rest z)))	                       ; Initialize lists and set to rest on every loop
    ((or (null x) (null y) (null z)))	               ; Break condition 
  (format t "~a~a~a~%" (first x) (first y) (first z))) ; On every loop print first elements

Output:

aA1
bB2
cC3

D

import std.stdio, std.range;

void main () {
    foreach (a, b, c; zip("abc", "ABC", [1, 2, 3]))
        writeln(a, b, c);
}

Output:

aA1
bB2
cC3

zip() allows to specify the stopping policy. On default it stops when the shortest range is exhausted (same as StoppingPolicy.shortest):

import std.stdio, std.range;

void main () {
    auto a1 = [1, 2];
    auto a2 = [1, 2, 3];
    alias StoppingPolicy sp;

    // Stops when the shortest range is exhausted
    foreach (p; zip(sp.shortest, a1, a2))
        writeln(p.tupleof);
    writeln();

    // Stops when the longest range is exhausted
    foreach (p; zip(sp.longest, a1, a2))
        writeln(p.tupleof);
    writeln();

    // Requires that all ranges are equal
    foreach (p; zip(sp.requireSameLength, a1, a2))
        writeln(p.tupleof);
}

Output:

Followed by an exception with message "Inequal-length ranges passed to Zip".

There is also std.range.lockstep:

import std.stdio, std.range;

void main() {
    auto arr1 = [1, 2, 3, 4, 5];
    auto arr2 = [6, 7, 8, 9, 10];

    foreach (ref a, ref b; lockstep(arr1, arr2))
        a += b;

    assert(arr1 == [7, 9, 11, 13, 15]);

    // Lockstep also supports iteration with an index variable
    foreach (index, a, b; lockstep(arr1, arr2))
        writefln("Index %s:  a = %s, b = %s", index, a, b);
}

Lower level code that stops at the shortest length:

import std.stdio, std.algorithm;

void main () {
    auto s1 = "abc";
    auto s2 = "ABC";
    auto a1 = [1, 2];

    foreach (i; 0 .. min(s1.length, s2.length, a1.length))
        writeln(s1[i], s2[i], a1[i]);
}

Output:

aA1
bB2

Delphi

program LoopOverArrays;

{$APPTYPE CONSOLE}

uses SysUtils;

const
  ARRAY1: array [1..3] of string = ('a', 'b', 'c');
  ARRAY2: array [1..3] of string = ('A', 'B', 'C');
  ARRAY3: array [1..3] of Integer = (1, 2, 3);
var
  i: Integer;
begin
  for i := 1 to 3 do
    Writeln(Format('%s%s%d', [ARRAY1[i], ARRAY2[i], ARRAY3[i]]));

  Readln;
end.

Diego

set_namespace(rosettacode);

add_mat(myMatrix)_row(a,b,c)_row(A,B,C)_row(1,2,3);
add_var(output,columnArray);

with_mat(myMatrix)_foreach()_bycol()_var(columnArray)
    with_var(output)_append()_flat([columnArray])_append(\n);
;

me_msg([output]);

reset_namespace[];

Diego has no issue when arrays are of a different length, the "missing" array entries will be handled as empty. Note, the matrix will become a clump, but can still be treated as a matrix.

set_ns(rosettacode);

add_clump(myClump)_row(a,b,c,d)_row(A,B,C,D,E,F)_row(-1,0,1,2,3);  // The default spread is presumed to be 'origin'
add_var(output,columnArray);

with_clump(myClump)_foreach()_bycol()_var(columnArray)
    with_var(output)_append()_flat([columnArray])_append(\n);
;

me_msg([output]);

reset_ns[];

Output:

aA-1
bB0
cC1
dD2
E3
F

DWScript

If the arrays don't have the same bounds, an index out of bound exception will be triggered when attempting to access a non-existing element.

const a1 = ['a', 'b', 'c'];
const a2 = ['A', 'B', 'C'];
const a3 = [1, 2, 3];

var i : Integer;
for i := 0 to 2 do
   PrintLn(Format('%s%s%d', [a1[i], a2[i], a3[i]]));

E

E lacks a nice way to do this; this is [http://wiki.erights.org/wiki/Parallel_iteration to be fixed, once we figure out what to do]. However, iteration over an List produces its indexes as keys, so a not entirely awful idiom exists:

def a1 := ["a","b","c"]
def a2 := ["A","B","C"]
def a3 := ["1","2","3"]

for i => v1 in a1 {
    println(v1, a2[i], a3[i])
}

This will obviously fail if a2 or a3 are shorter than a1, and omit items

if a2 or a3 are longer.

Given a parallel iteration utility, we might write this:

for [v1, v2, v3] in zip(a1, a2, a3) {
    println(v1, v2, v3)
}

zip cannot yet be defined for all collections (other than by iterating over each one and storing the results in a List

first); but we can define it for numeric-indexed collections such as

Lists, as below. Both a definition for any number of collections and two

collections is given; the latter in order to demonstrate the principle

without the clutter resulting from handling a variable number of collections.

def zip {
  to run(l1, l2) {
    def zipped {
      to iterate(f) {
        for i in int >= 0 {
          f(i, [l1.fetch(i, fn { return }),
                l2.fetch(i, fn { return })])
        }
      }
    }
    return zipped
  }

  match [`run`, lists] {
    def zipped {
      to iterate(f) {
        for i in int >= 0 {
          var tuple := []
          for l in lists {
            tuple with= l.fetch(i, fn { return })
          }
          f(i, tuple)
        }
      }
    }
    zipped
  }
}

(This will stop when the end of the shortest collection is reached.)

EchoLisp

;; looping over different sequences : infinite stream, string, list and vector
;; loop stops as soon a one sequence ends. 
;; the (iota 6) = ( 0 1 2 3 4 5) sequence will stop first.


(for ((i (in-naturals 1000)) (j "ABCDEFGHIJK") (k (iota 6)) (m #(o p q r s t u v w))) 
    (writeln i j k m))

1000     "A"     0     o    
1001     "B"     1     p    
1002     "C"     2     q    
1003     "D"     3     r    
1004     "E"     4     s    
1005     "F"     5     t

Ecstasy

module LoopOverMultipleArrays {
    void run() {
        Char[]   chars   = ['a', 'b', 'c'];
        String[] strings = ["A", "B", "C"];
        Int[]    ints    = [ 1,   2,   3 ];

        @Inject Console console;
        console.print("Using array indexing:");
        for (Int i = 0, Int longest = chars.size.maxOf(strings.size.maxOf(ints.size));
                i < longest; ++i) {
            console.print($|{i < chars.size   ? chars[i].toString() : ""}\
                           |{i < strings.size ? strings[i]          : ""}\
                           |{i < ints.size    ? ints[i].toString()  : ""}
                         );
        }

        console.print("\nUsing array iterators:");
        val charIter   = chars.iterator();
        val stringIter = strings.iterator();
        val intIter    = ints.iterator();
        while (True) {
            StringBuffer buf = new StringBuffer();
            if (Char ch := charIter.next()) {
                buf.add(ch);
            }
            if (String s := stringIter.next()) {
                s.appendTo(buf);
            }
            if (Int n := intIter.next()) {
                n.appendTo(buf);
            }
            if (buf.size == 0) {
                break;
            }
            console.print(buf);
        }
    }
}

Output:

Using array indexing:
aA1
bB2
cC3

Using array iterators:
aA1
bB2
cC3

Efene

@public 
run = fn () {
    lists.foreach(fn ((A, B, C)) { io.format("~s~n", [[A, B, C]]) }, 
lists.zip3("abc", "ABC", "123"))
}

If the lists are not all the same length, an error is thrown.

Eiffel

example (a_array: READABLE_INDEXABLE [BOUNDED [ANY]]): STRING
		-- Assemble output for a 2-dim array in `a_array'
	require
		non_zero: ∀ nzitem:a_array ¦ nzitem.count > 0
	local
		min_count: INTEGER
	do
		⟳ v_item:a_array ¦
			min_count := if min_count = 0 then
							v_item.count
						else
							v_item.count.min (min_count)
						end
		⟲
		create Result.make_empty
		⟳ j:1 |..| min_count ¦
			⟳ i:a_array ¦
				if attached {READABLE_INDEXABLE [ANY]} i as al_i then
					Result.append_string_general (al_i [j].out)
				end
			⟲
			Result.append_string_general ("%N")
		⟲
	end

input_data: ARRAY [BOUNDED [ANY]]
		-- Sample `input_data' for `example' (above).
	do
		Result := <<
						"abcde",
						"ABC",
						<<1, 2, 3, 4>>
					>>
	end

Output:

aA1

bB2

cC3

Explanation

The `require' Design-by-Contract assertion is a statement of software correctness. It states that all items in `a_array' must have a count > 0 (no empty of type BOUNDED).

If you examine the `input_data', you will see that collection 1 is not just "abc", but is "abcde" (5 character element items in a BOUNDED string). The same is true for the last numeric ARRAY, which has 4 integers. This is done to demonstrate that the `example' code is robust enough to take variants in the inputs in terms of item counts.

The first ⟳ ¦ ⟲ (symbolic across) loop seeks out the count of the smallest (min) collection. In this case, the middle item (#2) has only 3 elements, so this routine will only process the first 3 elements of each collection in the containing array.

Next, we create the output STRING in the `Result'.

Finally, the last ⟳ ¦ ⟲ (symbolic across) loop has a nested loop. The outer loop counts the elements (1-3) and the inner loop goes of the contained collections, adding the j-th element of the i-th collection. This repeats until all of `j' is exhausted for all of `i'.

Ela

open monad io list imperative
 
xs = zipWith3 (\x y z -> show x ++ show y ++ show z) ['a','b','c'] 
  ['A','B','C'] [1,2,3]

print x = do putStrLn x

print_and_calc xs = do
  xss <- return xs
  return $ each print xss

print_and_calc xs ::: IO

The code above can be written shorter. First there is no need in lists as soon as strings in Ela can be treated as lists. Also instead of explicit labmda one can use partial application and a standard composition operator:

xs = zipWith3 (\x -> (x++) >> (++)) "abc" "ABC"
 "123"

Elena

ELENA 5.0 :

import system'routines;
import extensions;

public program()
{  
    var a1 := new string[]{"a","b","c"};
    var a2 := new string[]{"A","B","C"};
    var a3 := new int[]{1,2,3};
    
    for(int i := 0, i < a1.Length, i += 1)
    {
        console.printLine(a1[i], a2[i], a3[i])
    };
    
    console.readChar()
}

Using zipBy extension:

import system'routines.
import extensions.

public program
{
    var a1 := new string[]{"a","b","c"};
    var a2 := new string[]{"A","B","C"};
    var a3 := new int[]{1,2,3};
    var zipped := a1.zipBy(a2,(first,second => first + second.toString() ))
                       .zipBy(a3, (first,second => first + second.toString() ));
    
    zipped.forEach:(e)
        { console.writeLine:e };
        
    console.readChar();
}

Output:

aA1
bB2
cC3

Elixir

string list:

l1 = ["a", "b", "c"]
l2 = ["A", "B", "C"]
l3 = ["1", "2", "3"]
IO.inspect List.zip([l1,l2,l3]) |> Enum.map(fn x-> Tuple.to_list(x) |> Enum.join end)
#=> ["aA1", "bB2", "cC3"]

char_list:

l1 = 'abc'
l2 = 'ABC'
l3 = '123'
IO.inspect List.zip([l1,l2,l3]) |> Enum.map(fn x-> Tuple.to_list(x) end)
#=> ['aA1', 'bB2', 'cC3']

When the length of the list is different:

iex(1)> List.zip(['abc','ABCD','12345']) |> Enum.map(&Tuple.to_list(&1))
['aA1', 'bB2', 'cC3']
iex(2)> List.zip(['abcde','ABC','12']) |> Enum.map(&Tuple.to_list(&1))
['aA1', 'bB2']

The zipping finishes as soon as any enumerable completes.

Erlang

Shortest option:

lists:zipwith3(fun(A,B,C)-> 
io:format("~s~n",[[A,B,C]]) end, "abc", "ABC", "123").

However, as every expression in Erlang has to return something, printing text returns 'ok'. A list with as many 'ok's as there are lines printed will thus be created. The technically cleanest way to do things would be with lists:foreach/2, which also guarantees evaluation order:

lists:foreach(fun({A,B,C}) ->  
io:format("~s~n",[[A,B,C]]) end,
              lists:zip3("abc", "ABC", "123")).

If the lists are not all the same length, an error is thrown.

Euphoria

There are many ways to do this. All of them rely on what strings really

are.

If they are all "strings", it's quite easy:

sequence a, b, c

a = "abc"
b = "ABC"
c = "123"

for i = 1 to length(a) do
    puts(1, a[i] & b[i] & c[i] & "\n")
end for

If not, and the other sequence is known to contain only integers:

sequence a, b, c

a = "abc"
b = "ABC"
c = {1, 2, 3}

for i = 1 to length(a) do
    printf(1, "%s%s%g\n", {a[i], b[i], c[i]})
end for

A general solution for any arbitrary strings of characters or numbers can get a bit complex. This is because of how sequences are stored and printed out. One possible answer is as follows, if you know that only alphanumeric characters are used:

for i = 1 to length(a) do
    if (a[i] >= '0' and a[i] <= '9') then
	a[i] -= '0'
    end if
    if (b[i] >= '0' and b[i] <= '9') then
	b[i] -= '0'
    end if
    if (c[i] >= '0' and c[i] <= '9') then
	c[i] -= '0'
    end if
    printf(1, "%s%s%s\n", {a[i], b[i], c[i]})
end for

Just as in Java, using single quotes around a character gives you its "char value". In Euphoria, though, it is simply that character's code in ASCII.

With all three of the above solutions, if any of the strings are smaller

than the first, it will return an error.

F#

for c1,c2,n in Seq.zip3 ['a';'b';'c'] ['A';'B';'C'] 
[1;2;3] do
  printfn "%c%c%d" c1 c2 n

When one sequence is exhausted, any remaining elements in the other sequences are ignored.

Factor

"abc" "ABC" "123" [ [ write1 ] tri@ nl ] 
3each

Fantom

This will stop when it reaches the end of the shortest list.

class LoopMultiple
{
  public static Void main ()
  {
    List arr1 := ["a", "b", "c"]
    List arr2 := ["A", "B", "C"]
    List arr3 := [1, 2, 3]
    [arr1.size, arr2.size, arr3.size].min.times |Int i|
    {
      echo ("${arr1[i]}${arr2[i]}${arr3[i]}")
    }
  }
}

Fermat

[a] := [('a','b','c')];
[b] := [('A','B','C')];
[c] := [(1,2,3)];
for i=1,3 do !!(a[i]:char,b[i]:char,c[i]:1) od;
;{note the :char and :1 suffixes. The former}
;{causes the element to be printed as a char}
;{instead of a numerical ASCII code, and the}
;{:1 causes the integer to take up exactly one}
;{space, ie. no leading or trailing spaces.}

Output:

aA1

bB2

cC3

Forth

create a  char a , char b , char c ,
create b  char A , char B , char C ,
create c  char 1 , char 2 , char 3 ,

: main
  3 0 do cr
    a i cells + @ emit
    b i cells + @ emit
    c i cells + @ emit
  loop
  cr
  a b c
  3 0 do cr
    3 0 do
      rot dup @ emit cell+
    loop
  loop
  drop drop drop
;

Fortran

program main
 implicit none

 integer,parameter :: n_vals = 3
 character(len=*),dimension(n_vals),parameter :: ls = ['a','b','c']
 character(len=*),dimension(n_vals),parameter :: us = ['A','B','C']
 integer,dimension(n_vals),parameter          :: ns = [1,2,3]

 integer :: i  !counter

 do i=1,n_vals
      write(*,'(A1,A1,I1)') ls(i),us(i),ns(i)
 end do

end program main

If the arrays are of different length (say, array ns has no third element), then when its turn comes the next unit of storage along from the second element will be accessed, its content interpreted as an integer, and its decimal value printed... If however, array bound checking is activated (or there is a memory access protection scheme that would detect this), a feature unavailable via many compilers and not the default on the rest, then an error will be detected and the run will be terminated, possibly with a somewhat helpful message.

If instead of reading the action had been to store a value into the array, then in the absence of bound checking, arbitrary damage will be done (to code or data) that will possibly result in something going wrong. And if you're lucky, it will happen swiftly.

Frink

a1 = ["a", "b", "c"]
a2 = ["A", "B", "C"]
a3 = ["1", "2", "3"]
m = [a1, a2, a3]
for row = m.transpose[]
   println[join["",row]]

FunL

import lists.zip3

for x <- zip3( ['a', 'b', 'c'], ['A', 'B', 'C'], [1, 2, 3] )
    println( x.mkString() )

Output:

aA1
bB2
cC3

FutureBasic

void local fn DoIt
  CFArrayRef a1 = @[@"a",@"b",@"c"]
  CFArrayRef a2 = @[@"A",@"B",@"C"]
  CFArrayRef a3 = @[@"1",@"2",@"3"]
  
  long i, count = len(a1)
  for i = 0 to count - 1
    print a1[i]a2[i]a3[i]
  next
end fn

fn DoIt

HandleEvents

Output:

aA1
bB2
Cc3

GAP

# The Loop function will apply some function to every tuple built by 
taking
# the i-th element of each list. If one of them is exhausted before the 
others,
# the loop continues at its begining. Only the longests lists will be 
precessed only once.
Loop := function(a, f)
    local i, j, m, n, v;
    n := Length(a);
    v := List(a, Length);
    m := Maximum(v);
    for j in [1 .. m] do
        f(List([1 .. n], i -> a[i][1 + RemInt(j - 1, v[i])]));
    od;
end;

# Here we simply print each "row"
f := function(u)
    Perform(u, Print);
    Print("\n");
end;

Loop([["a", "b", "c"], ["A", "B", "C"], [1, 2, 3]], f);

aA1
bB2
cC3

Loop([["a", "b"], ["A", "B", "C", "D", "E"], [1, 2, 3]], f);

aA1
bB2
aC3
bD1
aE2

GDScript

Works with: Godot version 4.0.1

extends MainLoop

# Implementation of zip, same length as the shortest array
func zip(lists: Array[Array]) -> Array[Array]:
	var length: int = lists.map(func(arr): return len(arr)).reduce(func(a,b): return min(a,b))
	var result: Array[Array] = []
	result.resize(length)
	for i in length:
		result[i] = lists.map(func(arr): return arr[i])
	return result

func _process(_delta: float) -> bool:
	var a: Array[String] = ["a", "b", "c"]
	var b: Array[String] = ["A", "B", "C"]
	var c: Array[String] = ["1", "2", "3"]

	for column in zip([a,b,c]):
		print(''.join(column))
	return true # Exit

Go

Go's "range clause" of a for statement only looks at a single iterable value (array, slice, etc). To access the three in parallel, they have to be explicitly indexed.

If a2 or a3 were shorter, the program would panic with "runtime error: index out of range". If a2 or a3 were longer, extra elements would be ignored. Go's philosophy is that you should explicitly check for whatever conditions are meaningful in your application and explicitly handle whatever errors are plausible.

package main

import "fmt"

var a1 = []string{"a", "b", "c"}
var a2 = []byte{'A', 'B', 'C'}
var a3 = []int{1, 2, 3}

func main() {
	for i := range a1 {
		fmt.Printf("%v%c%v\n", a1[i], a2[i], a3[i])
	}
}

Golfscript

["a" "b" "c"]:a;
["A" "B" "C"]:b;
["1" "2" "3"]:c;
[a b c]zip{puts}/

If there are arrays of different size, the shorter are treated as "null-padded" array.

Groovy

Solution:

def synchedConcat = { a1, a2, a3 ->
    assert a1 && a2 && a3
    assert a1.size() == a2.size()
    assert a2.size() == a3.size()
    [a1, a2, a3].transpose().collect { "${it[0]}${it[1]}${it[2]}" }
}

Test:

def x = ['a', 'b', 'c']
def y = ['A', 'B', 'C']
def z = [1, 2, 3]

synchedConcat(x, y, z).each { println it }

Output:

aA1
bB2
cC3

Harbour

Using FOR EACH ... NEXT statement

PROCEDURE Main()
	LOCAL a1 := { "a", "b", "c" }, ;
	      a2 := { "A", "B", "C", "D" }, ; // the last element "D" of this array will be ignored
	      a3 := { 1, 2, 3 }
	LOCAL e1, e2, e3
	
	FOR EACH e1, e2, e3 IN a1, a2, a3
		Qout( e1 + e2 + hb_ntos( e3 ) )
	NEXT
	RETURN

Output:

  aA1
  bB2
  cC3

If the arrays are not of equal length, the iteration stops after the last item of the smaller array has been processed; any extra items of lengthier arrays are ignored (or in other words, the iteration counter never exceeds the length of the smaller array, thus preventing an 'out of subscript range' error).

Haskell

Using list comprehension

{-# LANGUAGE ParallelListComp #-}

main :: IO [()]
main =
  sequence
    [ putStrLn [x, y, z]
      | x <- "abc"
      | y <- "ABC"
      | z <- "123"
    ]

Using Transpose

In this special case of transposing strings.

import Data.List
main = mapM putStrLn $ transpose ["abc", "ABC", "123"]

Using ZipWith*

import Data.List
main = mapM putStrLn $ zipWith3 (\a b c -> [a,b,c]) "abc" "ABC" "123"

Using applicative ZipLists

ZipLists generalize zipWith to any number of parameters

import Control.Applicative (ZipList (ZipList, getZipList))

main :: IO ()
main =
  mapM_ putStrLn $
    getZipList
      ( (\x y z -> [x, y, z])
          <$> ZipList "abc"
            <*> ZipList "ABC"
            <*> ZipList "123"
      )
      <> getZipList
        ( (\w x y z -> [w, x, y, z])
            <$> ZipList "abcd"
              <*> ZipList "ABCD"
              <*> ZipList "1234"
              <*> ZipList "一二三四"
        )

Output:

aA1
bB2
cC3
aA1一
bB2二
cC3三
dD4四

Haxe

using Lambda;
using Std;

class Main 
{
	
	static function main() 
	{
		var a = ['a', 'b', 'c'];
		var b = ['A', 'B', 'C'];
		var c = [1, 2, 3];
		
		//Find smallest array
		var len = [a, b, c]
			.map(function(a) return a.length)
			.fold(Math.min, 0x0FFFFFFF)
			.int();

		for (i in 0...len)
			Sys.println(a[i] + b[i] + c[i].string());
	}
}

HicEst

CHARACTER :: A = "abc"
REAL ::  C(3)

C = $ ! 1, 2, 3

DO i = 1, 3
   WRITE() A(i), "ABC"(i), C(i)
ENDDO

Icon and Unicon

The first solution uses co-expressions to produce parallel evaluation.

procedure main()
a := create !["a","b","c"]
b := create !["A","B","C"]
c := create !["1","2","3"]
while write(@a,@b,@c)
end

The second solution is more like other procedural languages and also handles unequal list lengths.

link numbers  # for max

procedure main()

a := ["a","b","c"]
b := ["A","B","C","D"]
c := [1,2,3]

every i := 1 to max(*a,*b,*c) do
   write(a[i]|"","\t",b[i]|"","\t",c[i]|"")
end

Library: Icon Programming Library

[http://www.cs.arizona.edu/icon/library/procs/numbers.htm Uses max from numbers]

Insitux

Translation of: Clojure

(map str "abc" "ABC" "123")
["aA1" "bB2" "cC3"]

(map str ["a" "b" "c"] ["A" "B" "C"] ["1" "2" "3"])
["aA1" "bB2" "cC3"]

J

Since J's primitives are designed for handling what some programmers might think of as "an array monad" of arbitrary rank, a natural approach would be to concatenate the multiple arrays into a single array. In many cases we would already have done so to pass these arrays as an argument to some user defined routine. So, let's first see how that could look:

For arrays of different types:

   ,.&:(":"0@>)/ 'abc' ; 'ABC' ; 1 2 3
aA1
bB2
cC3

This approach works by representing the digits as characters.

Where arrays are all the same type (all numeric or all string):

   ,.&:>/ 'abc' ; 'ABC' ; '123'
aA1
bB2
cC3

Both of these implementations reject arrays with conflicting lengths.

Other options include:

   |: 'abc', 'ABC' ,:;":&> 1 2 3
aA1
bB2
cC3

   |: 'abc', 'ABC',: '123'
aA1
bB2
cC3

These implementations pad short arrays with spaces.

Or:

   |:>]&.>L:_1 'abc';'ABC';<1 2 3
┌─┬─┬─┐
│a│A│1│
├─┼─┼─┤
│b│B│2│
├─┼─┼─┤
│c│C│3│
└─┴─┴─┘

This implementation puts each item from each of the original lists into a box and forms an array of boxes. (A "box" is a immutable pointer to immutable data -- in other words value semantics instead of reference semantics -- and "putting an item into a box" is obtaining one of these pointers for that item.) This implementation extends any short array by providing empty boxes to represent the missing elements. (An "empty box" is what a programmer in another language might call "a pointer to a zero length array".)

That said, it's also worth noting that a single explicit loop could also be used here. For example,

charcols=: {{
  'one two three'=. y
  for_a. one do.
    echo a,(a_index{two),":a_index{three
  end.
}}

   charcols 'abc';'ABC';1 2 3
aA1
bB2
cC3

Java

String[][] list1 = {{"a","b","c"}, {"A", "B", "C"}, {"1", "2", "3"}};
        for (int i = 0; i < list1.length; i++) {
            for (String[] lista : list1) {
                System.out.print(lista[i]);
            }
            System.out.println();
        }

JavaScript

Imperative

This loops over the indices of the first array, and uses that to index into the others.

var a = ["a","b","c"],
    b = ["A","B","C"],
    c = [1,2,3],
    output = "",
    i;
for (i = 0; i < a.length; i += 1) {
    output += a[i] + b[i] + c[i] + "\n";
}

If the b or c arrays are too "short", you will see the string "undefined" appear in the output.

Alternatively, we can nest a couple of calls to .forEach(): one for the array of three arrays, and one for each of the three index positions:

var lstOut = ['', '', ''];

[["a", "b", "c"], ["A", "B", "C"], ["1", "2", "3"]].forEach(
  function (a) {
    [0, 1, 2].forEach(
      function (i) {
        // side-effect on an array outside the function
        lstOut[i] += a[i];
      }
    );
  }
);

// lstOut --> ["aA1", "bB2", "cC3"]

Functional composition

ES5

Functional options include folding across an array of arrays with the built-in Array.reduce(), using a zipWith() function of suitable arity, or mapping over the output of a generic (any arity) zip() function.

(The generic zip function is the most tolerant – it simply ignores further elements in any arrays which are longer than the shortest array).

Reduce / fold:

(function (lstArrays) {

    return lstArrays.reduce(
        function (a, e) {
            return [
                a[0] + e[0],
                a[1] + e[1],
                a[2] + e[2]
            ];
        }, ['', '', ''] // initial copy of the accumulator
    ).join('\n');

})([
    ["a", "b", "c"],
    ["A", "B", "C"],
    ["1", "2", "3"]
]);

A fixed arity ZipWith:

(function (x, y, z) {

    // function of arity 3 mapped over nth items of each of 3 lists
    // (a -> b -> c -> d) -> [a] -> [b] -> [c] -> [d]
    function zipWith3(f, xs, ys, zs) {
        return zs.length ? [f(xs[0], ys[0], zs[0])].concat(
            zipWith3(f, xs.slice(1), ys.slice(1), zs.slice(1))) : [];
    }

    function concat(x, y, z) {
        return ''.concat(x, y, z);
    }

    return zipWith3(concat, x, y, z).join('\n')

})(["a", "b", "c"], ["A", "B", "C"], [1, 2, 3]);

Or we could write a generic zipListsWith applying some supplied function overs lists derived from the nth members of an arbitrary list of (equal-length) lists.

(function () {
    'use strict';

    // zipListsWith :: ([a] -> b) -> [[a]] -> [[b]]
    function zipListsWith(f, xss) {
        return (xss.length ? xss[0] : [])
            .map(function (_, i) {
                return f(xss.map(function (xs) {
                    return xs[i];
                }));
            });
    }

    // concat :: [a] -> s
    function concat(lst) {
        return ''.concat.apply('', lst);
    }

    // TEST
    return zipListsWith(
        concat, 
        [["a", "b", "c"], ["A", "B", "C"], [1, 2, 3]]
    )
    .join('\n');
})();

Output:

aA1
bB2
cC3

ES6

By transposition:

(() => {
    'use strict';

    // GENERIC FUNCTIONS -----------------------------------------------------

    // concat :: [[a]] -> [a]
    const concat = xs =>
        xs.length > 0 ? (() => {
            const unit = typeof xs[0] === 'string' ? '' : [];
            return unit.concat.apply(unit, xs);
        })() : [];

    // map :: (a -> b) -> [a] -> [b]
    const map = (f, xs) => xs.map(f);

    // transpose :: [[a]] -> [[a]]
    const transpose = xs =>
        xs[0].map((_, col) => xs.map(row => row[col]));

    // unlines :: [String] -> String
    const unlines = xs => xs.join('\n');

    // TEST ------------------------------------------------------------------
    const xs = [
        ['a', 'b', 'c'],
        ['A', 'B', 'C'],
        [1, 2, 3]
    ];

    return unlines(
        map(concat, transpose(xs))
    );
})();

Output:

aA1
bB2
cC3

jq

The following solution is based on the assumption that all the arrays can be presented as an array of arrays. This allows any number of arrays to be handled.

Specifically, zip/0 expects an array of 0 or more arrays as its input. The first array determines the number of items in the output; nulls are used for padding.

# zip/0 emits [] if input is [].

def zip:
  . as $in
  | [range(0; $in[0]|length) as $i | $in | map( .[$i] ) ];

Example 1:

[["a","b","c"], ["A","B","C"], [1,2,3]] | zip

Output:

 [["a","A",1],["b","B",2],["c","C",3]]

To obtain the compact output used in the the task description, we can filter the results through a "pretty-print" function:

def pp: reduce .[] as $i (""; . + "\($i)");

Example 2:

[["a","b","c"], ["A","B","C"], [1,2,3]] | zip | map(pp)

Output:

 [
  "aA1",
  "bB2",
  "cC3"
 ]

As already mentioned, the above definition of zip/0 privileges the first

array,

and if the subsequent arrays are of different lengths, null is used as a

filler.

Thus:

[["a","b","c"], ["A","B"], [1]] | zip

produces:

[["a","A",1],["b","B",null],["c",null,null]]

Handling jagged input An alternative approach would be use a variant of zip/0 that pads all arrays shorter than the longest with nulls. Here is such a variant:

# transpose a possibly jagged matrix
def transpose:
  if . == [] then []
  else (.[1:] | transpose) as $t
  | .[0] as $row
  | reduce range(0; [($t|length), (.[0]|length)] | max) as $i
         ([]; . + [ [ $row[$i] ] + $t[$i] ])
  end;

Jsish

/* Loop over multiple arrays, in Jsish */
var a1 = ['a', 'b', 'c'];
var a2 = ['A', 'B', 'C'];
var a3 = [1, 2, 3];

puts('Equal sizes');
var arr = [a1, a2, a3];
var m = arr[0].length;
for (var a of arr) if (a.length > m) m = a.length; 
for (var i = 0; i < m; i++) printf("%q%q%q\n", a1[i], a2[i], a3[i]);

puts('\nUnequal sizes');
var a4 = [];
var a5 = [4,5,6,7];

arr = [a1, a2, a3, a4, a5];
m = arr[0].length;
for (a of arr) if (a.length > m) m = a.length;
for (i = 0; i < m; i++) printf("%q%q%q%q%q\n", a1[i], a2[i], a3[i], a4[i], a5[i]);

/*
=!EXPECTSTART!=
Equal sizes
aA1
bB2
cC3

Unequal sizes
aA1undefined4
bB2undefined5
cC3undefined6
/home/btiffin/forge/jsi/jsi-test/rosetta/loopOverMultipleArrays.jsi:19: warn: call with undefined var for argument arg 2 '...', in call to 'printf' <undefined>.    (at or near "%q%q%q%q%q
")

undefinedundefinedundefinedundefined7
=!EXPECTEND!=
*/

Output:

prompt$ jsish -u loopOverMultipleArrays.jsi
[PASS] loopOverMultipleArrays.jsi

Julia

With a higher order function:

foreach(println, ('a', 'b', 'c'), ('A', 'B', 'C'), (1, 2, 3))

With a loop:

for (i, j, k) in zip(('a', 'b', 'c'), ('A', 'B', 'C'), (1, 2, 3))
    println(i, j, k)
end

Output:

aA1
bB2
cC3

K

{,/$x}'+("abc";"ABC";1 2 3)

Output:

("aA1"
 "bB2"
 "cC3")

If the length of the arrays are different, then K croaks with "length error".

The following is a more general approach where

      &/#:'x

calculates the minimum length of the arrays and is used to index the first elements in each array.

   {+x[;!(&/#:'x)]}("abc";"ABC";"1234")

Output:

("aA1"
 "bB2"
 "cC3")

If the arrays are of different type, then the arrays must be converted to strings.

   {a:,/'($:'x);+a[;!(&/#:'a)]}("abc";"ABC";1 2 3 4)

Kotlin

import kotlin.comparisons.minOf

fun main() {
    val a1 = charArrayOf('a', 'b', 'c')
    val a2 = charArrayOf('A', 'B', 'C')
    val a3 = intArrayOf(1, 2, 3)
    for (i in 0..2) println("${a1[i]}${a2[i]}${a3[i]}")
    println()
    // For arrays of different sizes, we can only iterate up to the size of the smallest array.
    val a4 = intArrayOf(4, 5, 6, 7)
    val a5 = charArrayOf('d', 'e')
    val minSize = minOf(a2.size, a4.size, a5.size)  // minimum size of a2, a4 and a5
    for (i in 0 until minSize) println("${a2[i]}${a4[i]}${a5[i]}")
}

Output:

aA1
bB2
cC3

A4d
B5e

Lambdatalk

1) loop over 3 sentences of equal length and returning 3 sentences

{def A a b c} -> A
{def B A B C} -> B
{def C 1 2 3} -> C

{S.map {lambda {:i} {br}{S.get :i {A}}
                        {S.get :i {B}} 
                        {S.get :i {C}} }
       {S.serie 0 {- {S.length {A}} 1}}}
-> 
a A 1 
b B 2 
c C 3

2) loop over 3 arrays of equal length and returning 3 arrays

{def maps
 {lambda {:a :b :c}
  {S.map {{lambda {:a :b :c :i} 
                 {br}{A.new {A.get :i :a} 
                            {A.get :i :b} 
                            {A.get :i :c}} } :a :b :c}
         {S.serie 0 {- {A.length :a} 1}}}}}
-> maps

{def P {A.new a b c}} -> P
{def Q {A.new A B C}} -> Q
{def R {A.new 1 2 3}} -> R

{maps {P} {Q} {R}}
-> 
[a,A,1] 
[b,B,2] 
[c,C,3]

3) loop over 3 words of inegal length and returning words

{def X James} -> X
{def Y Bond} -> Y
{def Z 007} -> Z

{S.map {lambda {:i} {br}{W.get :i {X}}
                        {W.get :i {Y}}
                        {W.get :i {Z}} }
       {S.serie 0 {- {W.length {X}} 1}}}
-> 
J B 0 
a o 0 
m n 7 
e d  
s

Lang

$a $= [a, b, c] # Char values
$b $= [A\e, B\e, C\e] # Text values
$c $= [1, 2, 3] # Int values

# Repeat loop
$i
repeat($[i], @$a) {
	fn.println(parser.op($a[$i] ||| $b[$i] ||| $c[$i]))
}
fn.println()

# Foreach loop with zip and reduce
$ele
foreach($[ele], fn.arrayZip($a, $b, $c)) {
	fn.println(fn.arrayReduce($ele, \e, fn.concat))
}
fn.println()

# Foreach function with combinator
fn.arrayForEach(fn.arrayZip($a, $b, $c), fn.combB(fn.println, fn.combC3(fn.arrayReduce, fn.concat, \e)))

Output:

aA1
bB2
cC3

aA1
bB2
cC3

aA1
bB2
cC3

LFE

(lists:zipwith3
  (lambda (i j k)
    (io:format "~s~s~p~n" `(,i ,j ,k)))
    '(a b c)
    '(A B C)
    '(1 2 3))

If any of the data lists differ in size from the other, the results will print out up to the shortest data list, and then raise a function_clause error.

Erlang, and thus LFE, have zipwith and zipwith3 for working with 2 and 3 simultaneous sets of data respectively. If you need more than that, you'll need to create your own "zip" function with something like (: lists map ...).

Lisaac

Section Header

+ name := ARRAY_LOOP_TEST;

Section Public

- main <- (
  + a1, a2 : ARRAY[CHARACTER];
  + a3 : ARRAY[INTEGER];

  a1 := ARRAY[CHARACTER].create 1 to 3;
  a2 := ARRAY[CHARACTER].create 1 to 3;
  a3 := ARRAY[INTEGER].create 1 to 3;

  1.to 3 do { i : INTEGER;
    a1.put ((i - 1 + 'a'.code).to_character) to i;
    a2.put ((i - 1 + 'A'.code).to_character) to i;
    a3.put i to i;
  };

  1.to 3 do { i : INTEGER;
    a1.item(i).print;
    a2.item(i).print;
    a3.item(i).print;
    '\n'.print;
  };
);

LiveCode

Arrays

command loopArrays
    local lowA, uppA, nums, z
    put "a,b,c" into lowA
    put "A,B,C" into uppA
    put "1,2,3" into nums
    
    split lowA by comma
    split uppA by comma
    split nums by comma

    repeat with n = 1 to the number of elements of lowA
        put lowA[n] & uppA[n] & nums[n] & return after z
    end repeat
    put z

end loopArrays

"list" processing

command loopDelimitedList
    local lowA, uppA, nums, z
    put "a,b,c" into lowA
    put "A,B,C" into uppA
    put "1,2,3" into nums

    repeat with n = 1 to the number of items of lowA
        put item n of lowA & item n of uppA & item n of nums 
& return after z
    end repeat
    put z

end loopDelimitedList

Output - both behave similarly for this exercise.

aA1
bB2
cC3

When there are fewer elements than the first (or whatever the loop is based on), livecode will add an "empty" value. If we add a "d" to lowA and a 4 to nums we get the following:

aA1
bB2
cC3
d4

Logo

Works with: UCB Logo

show (map [(word ?1 ?2 ?3)] [a b c] [A B C] [1 2 3])   
 ; [aA1 bB2 cC3]

(foreach [a b c] [A B C] [1 2 3] [print (word ?1 ?2 ?3)])  ; as above, 
one per line

Lua

This can be done with a simple for loop:

a1, a2, a3 = {'a' , 'b' , 'c' } , { 'A' , 'B' , 'C' } , { 1 , 2 , 3 }
for i = 1, 3 do print(a1[i]..a2[i]..a3[i]) end

but it may be more enlightening (and in line with the spirit of the challenge) to use the generic for:

function iter(a, b, c)
  local i = 0
  return function()
    i = i + 1
    return a[i], b[i], c[i]
  end
end

for u, v, w in iter(a1, a2, a3) do print(u..v..w) end

M2000 Interpreter

While End While can used for iterator type objects. We can use comma to use more than one iterator, or we can use folded While End While. When we use comma the iteration end when any of the iterators before iterate get the false state (no other iteration allowed). So for this example in While End while it is like we use i1 and i2 and i3, but with a comma (this only apply to While structure - and While { } structure - without End While^{Superscript text. We can't use and operator because this return Boolean type always. Using the iterator at While we get the object, and Interpreter check if this is an iterator object and go on to advance to next item, or to break the loop. We can use i1^ to get the index of the iteration according to specific object.}

module Loop_over_multiple_arrays_simultaneously {
	r1=("a","b","c",1,2,3,4,5)
	r2=("A","B","C", 4) 
	r3=(1,2,3)
	i1=each(r1)
	i2=each(r2)
	i3=each(r3)
	while i1, i2, i3
		print array(i1)+array(i2)+array(i3)
	end while
}
Loop_over_multiple_arrays_simultaneously

Output:

     aA1
     bB2
     cC3

Maple

# Set up
L := [["a", "b", "c"],["A", "B", "C"], ["1", "2", "3"]];
M := Array(1..3, 1..3, L);

multi_loop := proc(M)
	local i, j;
	for i from 1 to upperbound(M, 1) do
		for j from 1 to upperbound(M, 2) do
			printf("%s", M[j, i]);
		end do;
		printf("\n");
	end do;
end proc:

multi_loop(M);

Output:

aA1
bB2
cC3

Mathematica/Wolfram Language

This can be done with a built-in function:

MapThread[Print, {{"a", "b", "c"}, {"A", "B", "C"}, {1, 2, 3}}];

All arguments must be lists of the same length.

Maxima

/* Function that loops over multiple arrays simultaneously depending on the list with less length */
lomas(L):=block(
    minlen:lmin(map(length,L)),
    makelist(makelist(L[i][j],i,1,length(L)),j,1,minlen))$

/* Test case */
lst:[[a,b,c],[A,B,C],[1,2,3]]$
lomas(lst);

Output:

[[a,A,1],[b,B,2],[c,C,3]]

Mercury

:- module multi_array_loop.
:- interface.

:- import_module io.
:- pred main(io::di, io::uo) is det.

:- implementation.
:- import_module char, list, string.

main(!IO) :-
    A = ['a', 'b', 'c'],
    B = ['A', 'B', 'C'],
    C = [1, 2, 3],
    list.foldl_corresponding3(print_elems, A, B, C, !IO).

:- pred print_elems(char::in, char::in, int::in, io::di, io::uo) is det.

print_elems(A, B, C, !IO) :-
    io.format("%c%c%i\n", [c(A), c(B), i(C)], !IO).

The foldl_corresponding family of procedures all throw a software_error/1 exception if the lengths of the lists are not the same.

Modula-3

MODULE MultiArray EXPORTS Main;

IMPORT IO, Fmt;

TYPE ArrIdx = [1..3];

VAR 
  arr1 := ARRAY ArrIdx OF CHAR {'a', 'b', 'c'};
  arr2 := ARRAY ArrIdx OF CHAR {'A', 'B', 'C'};
  arr3 := ARRAY ArrIdx OF INTEGER {1, 2, 3};

BEGIN
  FOR i := FIRST(ArrIdx) TO LAST(ArrIdx) DO
    IO.Put(Fmt.Char(arr1[i]) & Fmt.Char(arr2[i]) & 
Fmt.Int(arr3[i]) & "\n");
  END;
END MultiArray.

MUMPS

Pieces of String version

LOOPMULT
 N A,B,C,D,%
 S A="a,b,c,d"
 S B="A,B,C,D"
 S C="1,2,3"
 S D=","
 F %=1:1:$L(A,",") W !,$P(A,D,%),$P(B,D,%),$P(C,D,%)
 K A,B,C,D,%
 Q

When there aren't enough elements, a null string will be returned from the $Piece function.

Output:

USER>d LOOPMULT^ROSETTA
 
aA1
bB2
cC3
dD

Local arrays version

LOOPMULU
 N A,B,C,D,%
 S A(1)="a",A(2)="b",A(3)="c",A(4)="d"
 S B(1)="A",B(2)="B",B(3)="C",B(4)="D"
 S C(1)="1",C(2)="2",C(3)="3"
 ; will error    S %=$O(A("")) F  Q:%=""  W !,A(%),B(%),C(%) S 
%=$O(A(%))
 S %=$O(A("")) F  Q:%=""  W !,$G(A(%)),$G(B(%)),$G(C(%)) S %=$O(A(%)) 
 K A,B,C,D,%

The commented out line will throw an <UNDEFINED> error when trying

to look up D(4). Using the $Get function as a wrapper means that if the
subscript for the array doesn't exist, a null string will be returned.

This same syntax is used for globals (permanent variables, that have a caret "^" as the first character).

Output:

USER>D LOOPMULU^ROSETTA
 
aA1
bB2
cC3
dD
USER>D LOOPMULV^ROSETTA

aA1
bB2
cC3
dD
 S %=$O(A("")) F  Q:%=""  W !,A(%),B(%),C(%) S %=$O(A(%))
                                        ^
<UNDEFINED>LOOPMULV+5^ROSETTA *C(4)

Nanoquery

Translation of: Java

list1 = {{"a","b","c"}, {"A","B","C"}, {"1","2","3"}}
for i in range(0, len(list1) - 1)
    for lista in list1
        print lista[i]
    end for
    println
end for

Nemerle

It "feels" better to use zip() for this, unfortunately the built in zip() only takes two lists.

using System;
using System.Console;

module LoopMultiple
{
    Zip3[T1, T2, T3] (x : list[T1], y : list[T2], z : list[T3]) : 
list[T1 * T2 * T3]
    {
        |(x::xs, y::ys, z::zs) => (x, y, z)::Zip3(xs, ys, zs)
        |([], [], [])          => []
        |(_, _, [])            => throw ArgumentNullException()
        |(_, [], _)            => throw ArgumentNullException()
        |([], _, _)            => throw ArgumentNullException()
    }
    
    Main() : void
    {
        def first  = ['a', 'b', 'c'];
        def second = ["A", "B", "C"];
        def third  = [1, 2, 3];
        
        foreach ((x, y, z) in Zip3(first, second, third))
            WriteLine($"$x$y$z");
    }
}

Alternately:

Translation of: C#

using System.Console;

module LoopMult
{
    Main() : void
    {
        def first  = array['a', 'b', 'c'];
        def second = array['A', 'B', 'C'];
        def third  = array[1, 2, 3];
        
        when (first.Length == second.Length && second.Length == 
third.Length)
            foreach (i in [0 .. (first.Length - 1)])
                WriteLine("{0}{1}{2}", first[i], second[i], third[i]);
    }
}

NetRexx

/* NetRexx */
options replace format comments java crossref savelog symbols nobinary

say 'Using arrays'
aa = ['a', 'b', 'c', 'd']
bb = ['A', 'B', 'C']
cc = [1, 2, 3, 4]

loop x_ = 0 for aa.length
  do
    ax = aa[x_]
  catch ArrayIndexOutOfBoundsException
    ax = ' '
  end
  do
    bx = bb[x_]
  catch ArrayIndexOutOfBoundsException
    bx = ' '
  end
  do
    cx = cc[x_]
  catch ArrayIndexOutOfBoundsException
    cx = ' '
  end

  say ax || bx || cx
  end x_

say 'Using indexed strings (associative arrays)'
ai = sampleData('a b c d')
bi = sampleData('A B C')
ci = sampleData('1 2 3 4')

loop x_ = 1 to ai[0]
  say ai[x_] || bi[x_] || ci[x_]
  end x_

method sampleData(arg) public static returns Rexx
  smp = ' '
  smp[0] = arg.words
  loop i_ = 1 to smp[0]
    smp[i_] = arg.word(i_)
    end i_
    
  return smp

Output:

Using arrays
aA1
bB2
cC3
d 4
Using indexed strings (associative arrays)
aA1
bB2
cC3
d 4

NewLISP

(map println '(a b c) '(A B C) '(1 2 
3))

Nim

let
  a = @['a','b','c']
  b = @["A","B","C"]
  c = @[1,2,3]

for i in 0..2:
  echo a[i], b[i], c[i]

Oberon-2

Works with oo2c version 2

MODULE LoopMArrays;
IMPORT 
	Out;
VAR
	x,y: ARRAY 3 OF CHAR;
	z: ARRAY 3 OF INTEGER;

PROCEDURE DoLoop;
VAR
	i: INTEGER;
BEGIN
	i := 0;
	WHILE i < LEN(x) DO
		Out.Char(x[i]);Out.Char(y[i]);Out.LongInt(z[i],0);Out.Ln;
		INC(i)
	END
END DoLoop;

BEGIN
	x[0] := 'a';y[0] := 'A';z[0] := 1;
	x[1] := 'b';y[1] := 'B';z[1] := 2;
	x[2] := 'c';y[2] := 'C';z[2] := 3;
	DoLoop
END LoopMArrays.

Output:

aA1
bB2
cC3

Objeck

class MultipleArrayAccess {
  function : Main(args : String[]) ~ Nil {
    a := ["a", "b", "c"];
    b := ["A", "B", "C"];
    c := [1, 2, 3];
    
    each(i : a) {
      a[i]->Append(b[i]);
      a[i]->Append(c[i]);
      a[i]->PrintLine();
    };
  }
}

If the arrays are different lengths, then an out-of-bounds error will be raised.

OCaml

an immediate solution:

let a1 = [| 'a'; 'b'; 'c' |]
and a2 = [| 'A'; 'B'; 'C' |]
and a3 = [| '1'; '2'; '3' |] ;;

Array.iteri (fun i c1 ->
  print_char c1;
  print_char a2.(i);
  print_char a3.(i);
  print_newline()
) a1 ;;

a more generic solution could be to use a function which iterates over a list of arrays:

let n_arrays_iter ~f = function
  | [] -> ()
  | x::xs as al ->
      let len = Array.length x in
      let b = List.for_all (fun a -> Array.length a = len) xs in
      if not b then invalid_arg "n_arrays_iter: arrays of different 
length";
      for i = 0 to pred len do
        let ai = List.map (fun a -> a.(i)) al in
        f ai
      done

this function raises Invalid_argument exception if arrays have different

length,

and has this signature:

val n_arrays_iter : f:('a list -> unit) -> 'a 
array list -> unit

how to use it with arrays a1, a2 and a3 defined before:

let () =
  n_arrays_iter [a1; a2; a3] ~f:(fun l ->
    List.iter print_char l;
    print_newline());
;;

Oforth

If arrays don't have the same size, zipAll reduces to the minimum size

[ "a", "b", "c" ] [ "A", "B", "C" ] [ 1, 2, 3 ] 
zipAll(3) apply(#[ apply(#print) printcr ])

Output:

aA1
bB2
cC3

ooRexx

x = .array~of("a", "b", "c")
y = .array~of("A", "B", "C")
z = .array~of(1, 2, 3)

loop i = 1 to x~size
    say x[i]y[i]z[i]
end

Oz

for
   I in [a b c]
   J in ['A' 'B' 'C']
   K in [1 2 3]
do
   {System.showInfo I#J#K}
end

The loop will stop when the shortest list is exhausted.

PARI/GP

This version stops when the shortest vector is exhausted.

loopMultiple(V)={
  my(l=#V[1]);
  for(i=2,#V,l=min(l,#V[i]));
  for(i=1,#V[1],
    for(j=1,#V,
      print1(V[j][i])
    );
    print()
  )
};

This version prints blanks when a vector is exhausted.

loopMultiple(V)={
  my(l=0);
  for(i=1,#V,l=max(l,#V[i]));
  for(i=1,#V[1],
    for(j=1,#V,
      if(#V[j]<i,
        print1(" ")
      ,
        print1(V[j][i])
      )
    );
    print()
  )
};

Pascal

See Delphi

Perl

sub zip (&@)
{
        my $code = shift;
        my $min;
        $min = $min && $#$_ > $min ? $min : $#$_ for @_;

        for my $i(0..$min){ $code->(map $_->[$i] ,@_) }
}
my @a1 = qw( a b c );
my @a2 = qw( A B C );
my @a3 = qw( 1 2 3 );

zip { print @_,"\n" }\(@a1, @a2, @a3);

This implementation will stop producing items when the shortest array ends.

Phix

Library: Phix/basics

Assumes a and b are strings and c is a sequence of integers.
If the arguments were not all the same length, attempts to retrieve non-existent elements could trigger a fatal run-time error, were it not for the min(). In print3, fairly obviously, we only extract up to the shortest length. The builtin columnize() routine can perform a similar task: I have provided a space defval and replaced the 3rd array with a string to ensure we get strings back, and extended it to show how columnize uses that default value for missing entries off the end of the first two arrays.

procedure print3(sequence a, b, c)
    for i=1 to min({length(a),length(b),length(c)}) do
        printf(1, "%s%s%g\n", {a[i], b[i], c[i]})
    end for
end procedure
 
print3("abc","ABC",{1, 2, 3})
?columnize({"abc","ABC","1234"},{},' ')

Output:

aA1
bB2
cC3
{"aA1","bB2","cC3","  4"}

Phixmonti

include ..\Utilitys.pmt

( "abc" "ABC" "123" )

len var dim1
1 get len var dim2 drop

dim1 for
    var i
    dim2 for
        var j
        ( j i ) sget tochar print
    endfor
    nl
endfor

PHP

$a = array('a', 'b', 'c');
$b = array('A', 'B', 'C');
$c = array('1', '2', '3'); //These don't *have* to be strings, but it 
saves PHP from casting them later

if ((sizeOf($a) !== sizeOf($b)) || (sizeOf($b) !== sizeOf($c))){
  throw new Exception('All three arrays must be the same length');
}
foreach ($a as $key => $value){
  echo "{$a[$key]}{$b[$key]}{$c[$key]}\n";
}

This implementation throws an exception if the arrays are not all the same length.

Picat

Picat has a built-in zip/n which only works with lists (not arrays). It returns an array tuple ({A,B,C}) and not a list ([A,B,C]), which is a typical gotcha.

For this task, a foreach loop and list comprenhension are shown.

If the lists/arrays are of uneven lengths, then the elements in the longer arrays are skipped.

import util.

go =>

  L1 = ["a","b","c"], 
  L2 = ["A","B","C"],
  L3 = ["1","2","3"],

  println("foreach loop:"),
  foreach({A,B,C} in zip(L1,L2,L3))
    println([A,B,C].join(''))
  end,
  nl,

  println("list comprehension/n:"),
  println( [[A,B,C].join('') : {A,B,C} in zip(L1,L2,L3)].join("\n")),
  nl,

  % With uneven lengths the last elements in the longer lists are skipped.
  println("Uneven lengths:"),
  L4 = ["P","Q","R","S"], % longer than the other
  foreach({A,B,C,D} in zip(L1,L2,L3,L4)) 
    println([A,B,C,D].join('')) 
  end,
  nl.

Output:

foreach loop:
aA1
bB2
cC3

list comprehension/n:
aA1
bB2
cC3

Uneven lengths:
aA1P
bB2Q
cC3R

PicoLisp

(mapc prinl
   '(a b c)
   '(A B C)
   (1 2 3) )

The length of the first argument list controls the operation. If subsequent lists are longer, their remaining values are ignored. If they are shorter, NIL is passed to the function.

Pike

Could be done with for, but foreachs included index counter avoids the usual off-by-one errors

    array a1 = ({ "a", "b", "c" });
    array a2 = ({ "A", "B", "C" });
    array a3 = ({ "1", "2", "3" });

    foreach(a1; int index; string char_dummy)
        write("%s%s%s\n", a1[index], a2[index], a3[index]);

Output:

aA1
bB2
cC3

PL/I

declare P(3) character (1) initial ('a', 'b', 'c'),
        Q(3) character (1) initial ('A', 'B', 'C'),
        R(3) fixed decimal (1) initial (1, 2, 3);

do i = lbound(P,1) to hbound(P,1);
   put skip edit (P(i), Q(i), R(i)) (2 A, F(1));
end;

PostScript

Library: initlib

% transpose is defined in initlib like this.
/transpose {
    [ exch {
        { {empty? exch pop} map all?} {pop exit} ift
        [ exch {} {uncons {exch cons} dip exch} fold counttomark 1 roll]
 uncons
    } loop ] {reverse} map
}.

% using it.
[[/a /b /c] [/A /B /C] [1 2 3]] transpose

PowerShell

A cheap and chEasy 'zip' function:

function zip3 ($a1, $a2, $a3)
{
    while ($a1)
    {
        $x, $a1 = $a1
        $y, $a2 = $a2
        $z, $a3 = $a3
        [Tuple]::Create($x, $y, $z)
    }
}

zip3 @('a','b','c') @('A','B','C') @(1,2,3)

Output:

Item1 Item2 Item3
----- ----- -----
a     A         1
b     B         2
c     C         3

zip3 @('a','b','c') @('A','B','C') @(1,2,3) | ForEach-Object {$_.Item1 + $_.Item2 + $_.Item3}

Output:

aA1
bB2
cC3

Prolog

Works with SWI-Prolog

multiple_arrays(L1, L2, L3) :-
	maplist(display, L1, L2, L3).

display(A,B,C) :-
	writef('%s%s%s\n', [[A],[B],[C]]).

Output:

 ?- multiple_arrays("abc", "ABC", "123").
aA1
bB2
cC3
true.

 ?- multiple_arrays("abc", "AB", "123").
aA1
bB2
false.

Python

Using zip():

>>> print ( '\n'.join(''.join(x) for x in 
zip('abc', 'ABC', '123')) )
aA1
bB2
cC3
>>>

If lists are different lengths, zip() stops after the shortest one.

Using map():

>>> print(*map(''.join, zip('abc', 'ABC', '123')), sep='\n')
aA1
bB2
cC3
>>>

If lists are different lengths, map() in Python 2.x pretends that the shorter lists were extended with None items; map() in Python 3.x stops after the shortest one.

Using itertools.imap() (Python 2.x):

from itertools import imap

def join3(a,b,c):
   print a+b+c

imap(join3,'abc','ABC','123')

If lists are differnt lengths, imap() stops after the shortest is exhausted.

Python 3.X has zip_longest which fills shorter iterables with its fillvalue argument which defaults to None (similar to the behavior of map() in Python 2.x):

>>> from itertools import zip_longest
>>> print ( '\n'.join(''.join(x) for x in zip_longest('abc', 
'ABCD', '12345', fillvalue='#')) )
aA1
bB2
cC3
#D4
##5
>>>

(The Python 2.X equivalent is itertools.izip_longest)

Quackery

The code presented here will loop as many times as the number of characters in the first nest (i.e. "abc" in the example). If either of the other two nests are shorter than the first then the program will report a problem.

  [ rot witheach
      [ emit 
        over i^ peek emit
        dup  i^ peek emit
        cr ]
    2drop ]               is task ( $ $ $ --> )

  $ "abc"  $ "ABC"  $ "123"  task

Output:

aA1
bB2
cC3

R

multiloop <- function(...)
{  
   # Retrieve inputs and convert to a list of character strings
   arguments <- lapply(list(...), as.character)
   
   # Get length of each input
   lengths <- sapply(arguments, length)

   # Loop over elements
   for(i in seq_len(max(lengths)))
   {
      # Loop over inputs
      for(j in seq_len(nargs()))
      {
         # print a value or a space (if that input has finished)
         cat(ifelse(i <= lengths[j], arguments[[j]][i], " "))
      }
      cat("\n")
   }
}
multiloop(letters[1:3], LETTERS[1:3], 1:3)

Same thing as a single function call. But throws error if the arrays differ in length.

apply(data.frame(letters[1:3], LETTERS[1:3], 1:3), 1,
      function(row) { cat(row, "\n", sep='') })

Racket

Racket for loops can loop over an arbitrary number of sequences of any kind at once:

#lang racket

(for ([x '(a b c)] ; list
      [y #(A B C)] ; vector
      [z "123"]
      [i (in-naturals 1)]) ; 1, 2, ... infinitely
  (printf "~s: ~s ~s ~s\n" i x y z))

The loop stops as soon as the first sequence terminates -- in the above case i can iterate forever but looping stops when we reach the end of the list/vector/string. (The same holds for multiple containers of different sizes.)

Raku

(formerly Perl 6)

Works with: rakudo version 2015.12

Note that all of the following work with any iterable object, (array, list, range, sequence; anything that does the Iterable role), not just arrays.

Basic functionality

for <a b c> Z <A B C> Z 1, 2, 3 -> ($x, $y, $z) {
   say $x, $y, $z;
}

The Z operator stops emitting items as soon as the shortest input list is exhausted. However, short lists are easily extended by replicating all or part of the list, or by appending any kind of lazy list generator to supply default values as necessary.

Since Z will return a list of lists (in this example, the first list is ('a', 'A', 1), parentheses are used around in the lambda signature ($x, $y, $z) to unpack the list for each iteration.

Factoring out concatenation

Note that we can also factor out the concatenation by making the Z metaoperator apply the ~ concatenation operator across each triple:

.say for <a b c> Z~ <A B C> Z~ 1, 2, 3;

We could also use the zip-to-string with the reduction metaoperator:

.say for [Z~] <a b c>, <A B C>, (1,2,3);

We could also write that out "long-hand":

.say for zip :with(&infix:<~>), <a b c>, <A B C>, (1,2,3);

returns the exact same result so if you aren't comfortable with the concise operators, you have a choice.

A list and its indices

The common case of iterating over a list and a list of its indices can be done using the same method:

for ^Inf Z <a b c d> -> ($i, $letter) { ... }

or by using the .kv (key and value) method on the list (and dropping the parentheses because the list returned by .kv is a flattened list):

for <a b c d>.kv -> $i, $letter { ... }

Iterate until all exhausted

If you have different sized lists that you want to pull a value from each per iteration, but want to continue until all of the lists are exhausted, we have roundrobin.

.put for roundrobin <a b c>, 'A'..'G', ^5;

yields:

a A 0
b B 1
c C 2
D 3
E 4
F
G

Red

The word repeat evaluates a given block! a specified number of times and exposes the count value to the block! being executed. When a variable is used in a path notation, we put a colon in front of it. :counter

>>blk: [["a" "b" "c"] ["A" "B" "C"] [1 2 3]]
== [["a" "b" "c"] ["A" "B" "C"] [1 2 3]]

>> repeat counter 3 [print [blk/1/:counter blk/2/:counter blk/3/:counter]]                                     
a A 1                                                                  
b B 2
c C 3

REXX

same size arrays

If any of the array's elements are missing or it is a short list, a blank is substituted to retain visual fidelity in the output.

When all elements are blank, then it signifies the end of the arrays.

/*REXX program shows how to  simultaneously  loop over  multiple arrays.*/
x. = ' ';      x.1 =  "a";      x.2 = 'b';      x.3 = "c"
y. = ' ';      y.1 =  "A";      y.2 = 'B';      y.3 = "C"
z. = ' ';      z.1 =  "1";      z.2 = '2';      z.3 = "3"

           do j=1  until output=''
           output = x.j || y.j || z.j
           say output
           end    /*j*/                /*stick a fork in it, we're done.*/

output

aA1
bB2
cC3

dissimilar sized arrays

In this example, two of the arrays are extended (past the 1^st example).
Also note that REXX doesn't require quotes around non-negative numbers (they're optional).

/*REXX program shows how to  simultaneously  loop over  multiple arrays.*/
x.=' ';      x.1="a";      x.2='b';      x.3="c";      x.4='d'
y.=' ';      y.1="A";      y.2='B';      y.3="C";
z.=' ';      z.1= 1 ;      z.2= 2 ;      z.3= 3 ;      z.4= 4;      z.5= 5

       do j=1  until output=''
       output=x.j || y.j || z.j
       say output
       end   /*j*/                     /*stick a fork in it, we're done.*/

output

aA1
bB2
cC3
d 4
  5

dissimilar sized lists

/*REXX program shows how to  simultaneously  loop over  multiple  lists.*/
x = 'a b c d'
y = 'A B C'
z =  1 2 3 4
               do j=1  until  output=''
               output = word(x,j) || word(y,j) || word(z,j)
               say output
               end    /*j*/            /*stick a fork in it, we're done.*/

output

aA1
bB2
cC3
d4

idiomatic method for lists

/*REXX program shows how to  simultaneously  loop over  multiple  lists.*/
x = 'a b c d'
y = 'A B C'
z =  1 2 3 4 ..LAST
                     do j=1  for max(words(x), words(y), words(z))
                     say word(x,j) || word(y,j) || word(z,j)
                     end    /*j*/      /*stick a fork in it, we're done.*/

output

aA1
bB2
cC3
d4
..LAST

Ring

array1 = ["a", "b", "c"]
array2 = ["A", "B", "C"]
array3 = [1, 2, 3]
 
for n = 1 to 3
    see array1[n] + array2[n] + array3[n] + nl
next

RPL

1993+ versions

≪ 3 ≪ + + ≫ DOLIST 
   OBJ→ DROP
≫ 'CONCAT3' STO

{ "a" "b" "c" } { "A" "B" "C" } { "1" "2" "3" } CONCAT3

Output:

3: "aA1"
2: "bB2"
1: "cC3"

Older versions

≪ → a b c
  ≪ 1 a SIZE FOR j
        a j GET b j GET c j GET + + 
     NEXT
≫ ≫'CONCAT3' STO

Ruby

['a','b','c'].zip(['A','B','C'], [1,2,3]) {|i,j,k| puts "#{i}#{j}#{k}"}

or

['a','b','c'].zip(['A','B','C'], [1,2,3]) {|a| puts a.join}

Both of these loops print aA1, bB2, cC3.

Array#zip iterates once for each element of the receiver. If an argument array is longer, the excess elements are ignored. If an argument array is shorter, the value nil is supplied.

irb(main):001:0> ['a','b','c'].zip(['A','B'], [1,2,3,4]) {|a| puts a.join}
aA1
bB2
c3
=> nil
irb(main):002:0> ['a','b','c'].zip(['A','B'], [1,2,3,4])
=> [["a", "A", 1], ["b", "B", 2], ["c", nil, 3]]

Rust

fn main() {
    let a1 = ["a", "b", "c"];
    let a2 = ["A", "B", "C"];
    let a3 = [1, 2, 3];

    for ((&x, &y), &z) in a1.iter().zip(a2.iter()).zip(a3.iter()) {
        println!("{}{}{}", x, y, z);
    }
}

Output:

aA1
bB2
cC3

Salmon

// First, we'll define a general-purpose zip() to zip
 any
// number of lists together.
function zip(...)
  {
    variable result;
    variable list_num := 0;
    iterate(arg; arguments)
      {
        variable elem_num := 0;
        iterate (x; arg)
          {
            result[elem_num][list_num] := x;
            ++elem_num;
          };
        ++list_num;
      };
    return result;
  };

immutable a := ["a", "b", "c"],
          b := ["A", "B", "C"],
          c := [1, 2, 3];
iterate (x; zip(a, b, c))
    print(x[0], x[1], x[2], "\n");;

The preceding code will throw an exception if the lists aren't the same length. Here's an example that will print a number of lines equal to the length of the longest list and print nothing for elements that are missing if some lists are shorter than the longest:

// First, we'll define a general-purpose zip() to zip
 any
// number of lists together.
function zip(...)
  {
    variable result := [];
    variable list_num := 0;
    iterate(arg; arguments)
      {
        variable elem_num := 0;
        iterate (x; arg)
          {
            if (elem_num >= length(result))
                result[elem_num] := <<(* --> "")>>;;
            result[elem_num][list_num] := x;
            ++elem_num;
          };
        ++list_num;
      };
    return result;
  };

immutable a := ["a", "b", "c"],
          b := ["A", "B", "C"],
          c := [1, 2, 3];
iterate (x; zip(a, b, c))
    print(x[0], x[1], x[2], "\n");;

Sather

class MAIN is
  main is
    a :ARRAY{STR} := |"a", "b", "c"|;
    b :ARRAY{STR} := |"A", "B", "C"|;
    c :ARRAY{STR} := |"1", "2", "3"|;
    loop
      #OUT + a.elt! + b.elt! + c.elt! + "\n";
    end;
  end;
end;

Scala

("abc", "ABC", "123").zipped foreach { (x, y, z) =>
  println(x.toString + y + z)
}

Scheme

Scheme provides for-each and map to iterate a function over one or more lists. The map form is used to collect the results into a new list.

(let ((a '("a" "b" "c"))
      (b '("A" "B" "C"))
      (c '(1 2 3)))
  (for-each 
    (lambda (i1 i2 i3) 
      (display i1) 
      (display i2) 
      (display i3) 
      (newline))
    a b c))

Scheme has a vector datatype with constant-time

retrieval of items held in an ordered sequence.  Use srfi-43 to get

similar iterators for vectors, vector-for-each and vector-map:

(let ((a (vector "a" "b" "c"))
      (b (vector "A" "B" "C"))
      (c (vector 1 2 3)))
  (vector-for-each
    (lambda (current-index i1 i2 i3)
      (display i1) 
      (display i2) 
      (display i3) 
      (newline))
    a b c))

Note, the lists or vectors must all be of the same length.

Sidef

The simplest way is by using the Array.zip{} method:

[%w(a b c),%w(A B C),%w(1 2 3)].zip { |i,j,k|
    say (i, j, k)
}

Output:

aA1
bB2
cC3

Smalltalk

Works with: GNU Smalltalk

|a b c|
a := OrderedCollection new addAll: #('a' 'b' 'c').
b := OrderedCollection new addAll: #('A' 'B' 'C').
c := OrderedCollection new addAll: #(1 2 3).

1 to: (a size) do: [ :i |
  (a at: i) display.
  (b at: i) display.
  (c at: i) displayNl.
].

If index i is out of bound, a runtime error is raised.

Actually, there is no need for the extra OrderedCollections as in the above example.
Also, most Smalltalks (all?) can concatenate non-string args¹.
At least in ST/X, the following works ¹:

|a b c|

a := #('a' 'b' 'c').
b := #('A' 'B' 'C').
c := #(1 2 3).
1 to: (a size) do: [ :i |
  ((a at: i),(b at: i),(c at: i)) displayNl.
].

Another alternative is to use a multi-collection enumerator, which hides the element access (transparent to how elements are stored inside the collection):

|a b c|

a := #('a' 'b' 'c').
b := #('A' 'B' 'C').
c := #(1 2 3).
a with:b with:c do:[:ai :bi :ci |
  (ai,bi,ci) displayNl.
].

1) concatenation of integer objects as shown above may require a change in the , (comma) implementation, to send "asString" to the argument.

SparForte

As a structured script.

#!/usr/local/bin/spar

pragma annotate( summary, "arrayloop" )
       @( description, "Loop over multiple arrays simultaneously" )
       @( category, "tutorials" )
       @( author, "Ken O. Burtch" )
       @( see_also, "http://rosettacode.org/wiki/Loop_over_multiple_arrays_simultaneously" );
pragma license( unrestricted );

pragma software_model( nonstandard );
pragma restriction( no_external_commands );

procedure arrayloop is
  a1 : constant array( 1..3 ) of character := ('a', 'b', 'c');
  a2 : constant array( 1..3 ) of character := ('A', 'B', 'C');
  a3 : constant array( 1..3 ) of integer   := (1, 2, 3);
begin
  for i in arrays.first( a1 )..arrays.last( a1 ) loop
      put( a1( i ) )
        @( a2( i ) )
        @( strings.trim( strings.image( a3( i ) ), trim_end.both ) );
      new_line;
  end loop;
end arrayloop;

Standard ML

The below code will combine arbitrarily many lists of strings into a single list with length equal to that of the shortest list.

(*
 * val combine_lists : string list list -> string list
 *)
fun combine_lists nil = nil
|   combine_lists (l1::ls) = List.foldl (ListPair.map (fn (x,y) => y ^
 x)) l1 ls;

(* ["a1Ax","b2By","c3Cz"] *)
combine_lists[["a","b","c"],["1","2","3"],["A","B","C"],["x","y","z"]];

Stata

Use an index variable.

local u a b c
local v A B C
matrix w=1,2,3
forv i=1/3 {
	di "`: word `i' of `u''`: word `i' of `v''`=el("w",1,`i')'"
}

Mata

mata
u="a","b","c"
v="A","B","C"
w=1,2,3

for (i=1; i<=3; i++) {
        printf("%s%s%f\n",u[i],v[i],w[i])
}
end

SuperCollider

Using three variables and indexing (SuperCollider posts the last statement in the REPL)

#x, y, z = [["a", "b", "c"], ["A", "B", "C"], ["1", "2", "3"]];
3.collect { |i| x[i] ++ y[i] ++ z[i] }

A more idiomatic way of writing it, independent of the number of dimensions:

[["a", "b", "c"], ["A", "B", "C"], ["1", "2", "3"]].flop.collect { |x| x.join }

Or simpler:

[["a", "b", "c"], ["A", "B", "C"], ["1", "2", "3"]].flop.collect(_.join)

Same with lamination (a concept from APL/J):

["a", "b", "c"] +++ ["A", "B", "C"] +++ ["1", "2", "3"]

Independent of dimensions:

[["a", "b", "c"], ["A", "B", "C"], ["1", "2", "3"]].reduce('+++')

Swift

let a1 = ["a", "b", "c"]
let a2 = ["A", "B", "C"]
let a3 = [1, 2, 3]

for i in 0 ..< a1.count {
    println("\(a1[i])\(a2[i])\(a3[i])")
}

Output:

aA1
bB2
cC3

Tailspin

Simplest iteration with an ordinary "loop" that will error on uneven sizes

def x: ['a', 'b', 'c'];
def y: ['A', 'B', 'C'];
def z: [1, 2, 3];

1..$x::length -> '$x($);$y($);$z($);
' -> !OUT::write

Output:

aA1
bB2
cC3

A simple transpose method that gives the same output and also errors on uneven sizes

templates transpose
  def a: $;
  def n: $(1)::length;
  [ 1..$n -> $a(1..last; $) ] !
end transpose

[$x, $y, $z] -> transpose... -> '$...;
' -> !OUT::write

A more complex transpose that uses "foreach" more in line with the task proposal and handles uneven arrays

def u: ['a', 'b'];
def v: ['A', 'B', 'C'];
def w: [1];

templates transpose2
  @: [];
  $... -> \[i](
    when <?($i <..$@transpose2::length>)> do ..|@transpose2($i): $;
    otherwise ..|@transpose2: [$];\) -> !VOID
  $@ !
end transpose2

[$x, $y, $z] -> transpose2... -> '$...;
' -> !OUT::write

'
' -> !OUT::write

[$u,$v,$w] -> transpose2... -> '$...;
' -> !OUT::write

Output:

aA1
bB2
cC3

aA1
bB
C

Tcl

set list1 {a b c}
set list2 {A B C}
set list3 {1 2 3}
foreach i $list1 j $list2 k $list3 {
    puts "$i$j$k"
}

If lists are different lengths, the manual [1] says: "The total number of loop iterations is large enough to use up all the values from all the value lists. If a value list does not contain enough elements for each of its loop variables in each iteration, empty values are used for the missing elements."

TorqueScript

$var[0] = "a b c"
$var[1] = "A B C";
$var[2] = "1 2 3";

for(%i=0;%i<3;%i++)
	echo(getWord($var[0],%i) @ getWord($var[1],%i) @ getWord($var[2],%i));

TUSCRIPT

$$ MODE TUSCRIPT
arr1="a'b'c"
arr2="a'b'C"
arr3="1'2'3"
LOOP a=arr1,b=arr2,c=arr3
PRINT a,b,c
ENDLOOP

Output:

aa1
bb2
cC3

TXR

Pattern language

$ txr -c '@(bind a ("a" "b" "c"))
@(bind b ("A" "B" "C"))
@(bind c ("1" "2" "3"))
@(output)
@  (repeat)
@a@b@c
@  (end)
@(end)'
aA1
bB2
cC3

TXR Lisp, using `mapcar`

Here we actually loop over four things: three strings and an infinite list of newlines. The output is built up as one string object that is finally printed in one go.

$ txr -e '(pprint (mappend (op list) "abc" "ABC" "123" 
(repeat "\n")))'
aA1
bB2
cC3

TXR Lisp, using `each`

$ txr -e '(each ((x "abc") (y "ABC") (z "123")) 
(put-line `@x@y@z`))'
aA1
bB2
cC3

Translation of Scheme

Translation of: Scheme

;; Scheme's vector-for-each: a one-liner in TXR
;; that happily works over strings and lists.
;; We don't need "srfi-43".
(defun vector-for-each (fun . vecs)
  [apply mapcar fun (range) vecs])

(defun display (obj : (stream *stdout*))
  (pprint obj stream))

(defun newline (: (stream *stdout*))
  (display #\newline stream))

(let ((a (vec "a" "b" "c"))
      (b (vec "A" "B" "C"))
      (c (vec 1 2 3)))
  (vector-for-each
    (lambda (current-index i1 i2 i3)
      (display i1)
      (display i2)
      (display i3)
      (newline))
    a b c))

Translation of Logo

Translation of: Logo

(macro-time
  (defun question-var-to-meta-num (var)
    ^(sys:var ,(int-str (cdr (symbol-name var))))))

(defmacro map (square-fun . square-args)
  (tree-bind [(fun . args)] square-fun
    ^[apply mapcar (op ,fun ,*[mapcar question-var-to-meta-num args])
            (macrolet ([(. args) ^(quote ,args)])
               (list ,*square-args))]))

(defun word (. items)
  [apply format nil "~a~a~a" items])

(defun show (x) (pprinl x))

(show (map [(word ?1 ?2 ?3)] [a b c] [A B C] [1 2 3]))

Output:

(aA1 bB2 cC3)

TypeScript

// Loop over multiple arrays simultaneously
var arr1: string[] = ['a', 'b', 'c'];
var arr2: string[] = ['A', 'B', 'C'];
var arr3: number[] = [1, 2, 3];
for (var i = 0; i <= 2; i++)
  console.log(`${arr1[i]}${arr2[i]}${arr3[i]}`);

Output:

aA1
bB2
cC3

UNIX Shell

With the Bourne shell, its for loop (from Loops/Foreach#UNIX Shell) can iterate only one list. We use an index i to access the other lists: set -- $list loads the positional parameters, and shift $i moves our element to $1.

Works with: Bourne Shell

a=a:b:c
b=A:B:C
c=1:2:3

oldifs=$IFS
IFS=:
i=0
for wa in $a; do
	set -- $b; shift $i; wb=$1
	set -- $c; shift $i; wc=$1

	printf '%s%s%s\n' $wa $wb $wc

	i=`expr $i + 1`
done
IFS=$oldifs

Output:

aA1
bB2
cC3

When the lists have different lengths, this code uses the length of list

a. Longer lists ignore their extra elements,

and shorter lists give extra empty strings.

Inspired by the previous example, below is the way to loop over two arrays simultaneously using set -- $ARGS. It is less general than the previous example but it is shorter and works just fine.

Works with: Bourne Shell

A='a1 a2 a3'
B='b1 b2 b3'

set -- $B
for a in $A
do
    printf "$a $1\n"
    shift
done

Output:

a1 b1
a2 b2
a3 b3

Some shells have real arrays, so the iteration is much more simple and easy.

Works with: bash

Works with: ksh93

a=(a b c)
b=(A B C)
c=(1 2 3)
for ((i = 0; i < ${#a[@]}; i++)); do
  echo "${a[$i]}${b[$i]}${c[$i]}"
done

Output:

aA1
bB2
cC3

Works with: ksh93

Works with: pdksh

set -A a a b c
set -A b A B C
set -A c 1 2 3
((i = 0))
while ((i < ${#a[@]})); do
  echo "${a[$i]}${b[$i]}${c[$i]}"
  ((i++))
done

Works with: zsh

a=(a b c)
b=(A B C)
c=(1 2 3)
for ((i = 1; i <= $#a; i++)); do
  echo "$a[$i]$b[$i]$c[$i]"
done

C Shell

Uses the length of array a. Longer arrays ignore their extra elements, but shorter arrays force the shell to exit with an error like b: Subscript out of range.

set a=(a b c)
set b=(A B C)
set c=(1 2 3)
@ i = 1
while ( $i <= $#a )
	echo "$a[$i]$b[$i]$c[$i]"
	@ i += 1
end

Ursa

Looping over multiple arrays in an interactive session:

> decl string<> a b c
> append (split "abc" "") a
> append (split "ABC" "") b
> append (split "123" "") c
> for (decl int i) (< i (size a)) (inc i)
..	out a<i> b<i> c<i> endl console
..end
aA1
bB2
cC3
> _

If either of the arrays are smaller than (size a), then an indexerror is thrown. This could be caught with a try...catch block.

Ursala

Compute the transpose of the list formed of the three lists. If they're of unequal lengths, an exception occurs.

#show+

main = ~&K7 <'abc','ABC','123'>

Output:

aA1
bB2
cC3

Vala

const char a1[] = {'a','b','c'};
const char a2[] = {'A','B','C'};
const int a3[] = {1, 2, 3};

void main() {
  for (int i = 0; i < 3; i++)
    stdout.printf("%c%c%i\n", a1[i], a2[i], a3[i]);
}

VBScript

' Loop over multiple arrays simultaneously - VBScript - 08/02/2021

a = Array("a","b","c")
b = Array("A","B","C")
c = Array(1,2,3)
For i = LBound(a) To UBound(a)
    buf = buf & vbCrLf & a(i) & b(i) & c(i)
Next
WScript.Echo Mid(buf,3)

Output:

aA1
bB2
cC3

VBA

Works with: VBA version VBA Excel 2013

' Loop over multiple arrays simultaneously - VBA - 08/02/2021

Sub Main()
	a = Array("a","b","c")
	b = Array("A","B","C")
	c = Array(1,2,3)
	For i = LBound(a) To UBound(a)
		buf = buf & vbCrLf & a(i) & b(i) & c(i)
	Next
	Debug.Print Mid(buf,3)
End Sub

Output:

aA1
bB2
cC3

Visual FoxPro

LOCAL i As Integer, n As Integer, c As String
LOCAL ARRAY a1[3], a2[3], a3[4], a[3]
*!* Populate the arrays and store the array lengths in a
a1[1] = "a"
a1[2] = "b"
a1[3] = "c"
a[1] = ALEN(a1)
a2[1] = "A"
a2[2] = "B"
a2[3] = "C"
a[2] = ALEN(a2)
a3[1] = "1"
a3[2] = "2"
a3[3] = "3"
a3[4] = "4"
a[3] = ALEN(a3)
*!* Find the maximum length of the arrays
*!* In this case, 4
n = MAX(a[1], a[2], a[3])
? "Simple Loop"
FOR i = 1 TO n
    c = ""
    c = c + IIF(i <= a[1], a1[i], "#")
    c = c + IIF(i <= a[2], a2[i], "#")
    c = c + IIF(i <= a[3], a3[i], "#")
   ? c
ENDFOR
*!* Solution using a cursor
CREATE CURSOR tmp (c1 C(1), c2 C(1), c3 C(1), c4 C(3))
INSERT INTO tmp (c1, c2, c3) VALUES ("a", "A", "1")
INSERT INTO tmp (c1, c2, c3) VALUES ("b", "B", "2")
INSERT INTO tmp (c1, c2, c3) VALUES ("c", "C", "3")
INSERT INTO tmp (c1, c2, c3) VALUES ("#", "#", "4")
REPLACE c4 WITH c1 + c2 + c3 ALL
? "Solution using a cursor"
LIST OFF FIELDS c4

Output:

Simple Loop
aA1
bB2
cC3
##4

Solution using a cursor

aA1
bB2
cC3
##4

V (Vlang)

fn main() {
    arrays := [['a','b','c'],['A','B','C'],['1','2','3']]
    for i in 0..arrays[0].len {
        println('${arrays[0][i]}${arrays[1][i]}${arrays[2][i]}')
    }
}

Wart

each (x X n) (zip '(a b c) '(A B C) '(1 2 3))
  prn x X n

Wren

The following script will work as expected provided the lengths of a1 and a2 are at least equal to the length of a3. Otherwise it will produce a 'Subscript out of bounds' error.

var a1 = ["a", "b", "c"]
var a2 = ["A", "B", "C"]
var a3 = [1, 2, 3]
for (i in a3) System.print("%(a1[i-1])%(a2[i-1])%(i)")

Output:

aA1
bB2
cC3

X86 Assembly

Works with: nasm

Works with: windows

extern _printf

section .data
    arr1 dd 3,"a","b","c" ;first dword saves the length
    arr2 dd 3,"A","B","C"
    arr3 dd 3,"1","2","3"
    
section .bss
    arrLocation resd 4
    tempOutput resd 2

section .text
global _main
_main:
    mov [arrLocation], dword arr1
    mov [arrLocation+4], dword arr2
    mov [arrLocation+8], dword arr3
    mov [arrLocation+12], dword 0 ;signales end
    mov [tempOutput+4], dword 0 ;dword 0 signales end of string
    
    mov ecx, 1 ;not 0 as in 0 the length is saved
    looping:
        mov ebx, 0 ;0 as arrLocation doesn't save length
        inloop:
            mov eax, [arrLocation+ebx*4] ;get ebxth arr address
            cmp eax, 0 ;if we don't get an address incresse index
            je incecx
            cmp ecx, [eax] ;when ecx is greater then the length of the current array we end
            jg end
            mov edx, [eax + ecx*4] ;get char at index ecx from arr
            mov [tempOutput], edx ;setup for _printf
            push ecx ;save ecx
            push tempOutput ;parameter for _printf
            call _printf
            add esp, 4 ;garbage collecting
            pop ecx ;restore ecx
            inc ebx ;get next arr
            jmp inloop
    incecx:
        mov [tempOutput], dword 0x0a ;after we print every element at the nth index we print a \n
        push ecx
        push tempOutput
        call _printf
        add esp, 4
        pop ecx
        inc ecx ;increase index
        jmp looping
        
    end:
        xor eax, eax
        ret

XPL0

string 0;               \use zero terminated strings
include c:\cxpl\codes;  \intrinsic 'code' declarations
char A1, A2;
int A3, I;
[A1:= "abc";
 A2:= "ABC";
 A3:= [1,2,3];
 for I:= 0 to 2 do
        [ChOut(0, A1(I));
         ChOut(0, A2(I));
        IntOut(0, A3(I));
        CrLf(0);
        ];
]

Output:

aA1
bB2
cC3

Z80 Assembly

org &1000


ld b,3
ld ix,array1
loop:
ld a,(ix)
call &bb5a   ;prints character to screen
ld a,(ix+3)
call &bb5a
ld a,(ix+6)
call &bb5a
ld a,13
call &bb5a
ld a,10
call &bb5a
inc ix
djnz loop



ret
array1:
  db "abc"
array2:
  db "ABC"
array3:
  db "123"

Output:

Ready
call &1000
aA1
bB2
cC3
Ready

The program was only written to display the first 3 characters. If they were of different lengths, the wrong characters (or random bytes outside the program) would have been read, depending on which array "ran out" first. The three arrays defined with the db directive are stored sequentially.

zkl

foreach a,b,c in (["a".."c"].zip(T("A","B","C"),[1..])){ println(a,b,c) }

or

Utils.zipWith(False,fcn{vm.arglist.concat().println()},
   ["a".."c"],T("A","B","C"),[1..])

Output:

aA1
bB2
cC3

zip[With] stops at the end of the shortest sequence, which means it can work with infinite sequences

Zig

Limit by minimum length

Works with: 0.10.x

const std = @import("std");

const arr1 = [_]u8{ 'a', 'b', 'c' };
const arr2 = [_]u8{ 'A', 'B', 'C' };
const arr3 = [_]u8{ '1', '2', '3' };

pub fn main() std.fs.File.WriteError!void {
    const stdout = std.io.getStdOut();
    const stdout_w = stdout.writer();
    const n = std.math.min3(arr1.len, arr2.len, arr3.len);
    for (arr1[0..n]) |arr1_e, i| {
        try stdout_w.print("{c} {c} {c}\n", .{ arr1_e, arr2[i], arr3[i] });
    }
}

Works with: 0.11.x, 0.12.0-dev.1381+61861ef39

const std = @import("std");

const arr1 = [_]u8{ 'a', 'b', 'c' };
const arr2 = [_]u8{ 'A', 'B', 'C' };
const arr3 = [_]u8{ '1', '2', '3' };

pub fn main() std.fs.File.WriteError!void {
    const stdout = std.io.getStdOut();
    const stdout_w = stdout.writer();
    const n = @min(arr1.len, arr2.len, arr3.len);
    for (arr1[0..n], arr2[0..n], arr3[0..n]) |arr1_e, arr2_e, arr3_e| {
        try stdout_w.print("{c} {c} {c}\n", .{ arr1_e, arr2_e, arr3_e });
    }
}

Limit by length of first array

Works with: 0.10.x

This example will print up-to arr1 length (asserts that other arrays are at least that long).

const std = @import("std");

const arr1 = [_]u8{ 'a', 'b', 'c' };
const arr2 = [_]u8{ 'A', 'B', 'C' };
const arr3 = [_]u8{ '1', '2', '3' };

pub fn main() std.fs.File.WriteError!void {
    const stdout = std.io.getStdOut();
    const stdout_w = stdout.writer();
    for (arr1) |arr1_e, i| {
        try stdout_w.print("{c} {c} {c}\n", .{ arr1_e, arr2[i], arr3[i] });
    }
}

Works with: 0.11.x, 0.12.0-dev.1381+61861ef39

const std = @import("std");

const arr1 = [_]u8{ 'a', 'b', 'c' };
const arr2 = [_]u8{ 'A', 'B', 'C' };
const arr3 = [_]u8{ '1', '2', '3' };

pub fn main() std.fs.File.WriteError!void {
    const stdout = std.io.getStdOut();
    const stdout_w = stdout.writer();
    for (arr1, 0..) |arr1_e, i| {
        try stdout_w.print("{c} {c} {c}\n", .{ arr1_e, arr2[i], arr3[i] });
    }
}

Assert that arrays have equal length

Works with: 0.11.x, 0.12.0-dev.1381+61861ef39

This example will print up-to arr1 length (asserts that other arrays are exactly that long => asserts that lengths are equal).

const std = @import("std");

const arr1 = [_]u8{ 'a', 'b', 'c' };
const arr2 = [_]u8{ 'A', 'B', 'C' };
const arr3 = [_]u8{ '1', '2', '3' };

pub fn main() std.fs.File.WriteError!void {
    const stdout = std.io.getStdOut();
    const stdout_w = stdout.writer();
    for (arr1, arr2, arr3) |arr1_e, arr2_e, arr3_e| {
        try stdout_w.print("{c} {c} {c}\n", .{ arr1_e, arr2_e, arr3_e });
    }
}