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Task

Determine the amount of elements in an array.

As an example use an array holding the strings 'apple' and 'orange'.

Other tasks related to string operations:

Metrics

Counting

Remove/replace

Anagrams/Derangements/shuffling

Find/Search/Determine

Formatting

Song lyrics/poems/Mad Libs/phrases

Tokenize

Sequences

360 Assembly

Array length is computed at compilation time with the formula : (AEND-A)/L'A

*        Array length              22/02/2017
ARRAYLEN START
         USING ARRAYLEN,12
         LR    12,15               end of prolog
         LA    1,(AEND-A)/L'A      hbound(a)
         XDECO 1,PG+13             edit
         XPRNT PG,L'PG             print
         BR    14                  exit
A        DC    CL6'apple',CL6'orange'   array
AEND     DC    0C
PG       DC    CL25'Array length='      buffer
         END   ARRAYLEN

Output:

Array length=           2

Array length is computed at compilation time with the formula: (Array_End-Array). Even though the labels Array and Array_End are both 16-bit values, if their difference fits into 8 bits the assembler will allow you to load it into a register.

start:
LDA #(Array_End-Array)   ;evaluates to 13
RTS

Array:
byte "apple",0
byte "orange",0
Array_End:

68000 Assembly

Array length is computed at compilation time with the formula: (Array_End-Array). The "bit width" of this value is the bit width of the result, not the bit width of the inputs. In other words, even though code labels are 32-bit memory addresses, if their difference is 8 or 16-bit you can use a .B or .W instruction or directive on them without a compile-time error.

The biggest limitation to the (Array_End-Array) method is that it always measures in total bytes. So if your array elements are of a different type you'll have to adjust accordingly. For an array strings, you should instead construct an array of pointers to strings and divide the result of the difference by 4 to get the total number of "strings" in the array.

start:
MOVE.B #(MyArray_End-MyArray)/4   ;evaluates to 2
RTS

Apple:
DC.B "apple",0
even
Orange:
DC.B "orange",0
even

MyArray:
DC.L Apple
DC.L Orange
MyArray_End:

8th

["apples", "oranges"] a:len . cr

Output:

AArch64 Assembly

Works with: as version Raspberry Pi 3B version Buster 64 bits

/* ARM assembly AARCH64 Raspberry PI 3B */
/*  program lenAreaString64.s   */
 
/*******************************************/
/* Constantes file                         */
/*******************************************/
/* for this file see task include a file in language AArch64 assembly*/
.include "../includeConstantesARM64.inc"
/*******************************************/
/* Initialized data                        */
/*******************************************/
.data
szMessLenArea:     .asciz "The length of area is :  @ \n"
szCarriageReturn:  .asciz "\n"
 
/* areas strings  */
szString1:  .asciz "Apples"
szString2:  .asciz "Oranges"
/* pointer items area */
tablesPoi:
ptApples:    .quad szString1
ptOranges:   .quad szString2
ptVoid:      .quad 0
/*******************************************/
/* UnInitialized data                      */
/*******************************************/
.bss 
sZoneConv:   .skip 30
/*******************************************/
/*  code section                           */
/*******************************************/
.text
.global main 
main:                        // entry of program
 
    ldr x1,qAdrtablesPoi     // begin pointer table 
    mov x0,0                 // counter
1:                           // begin loop
    ldr x2,[x1,x0,lsl 3]     // read string pointer address item x0 (8 bytes by pointer)
    cmp x2,0                 // is null ?
    cinc x0,x0,ne            // no increment counter
    bne 1b                   // and loop
 
    ldr x1,qAdrsZoneConv     // conversion decimal
    bl conversion10S
    ldr x0,qAdrszMessLenArea
    ldr x1,qAdrsZoneConv 
    bl strInsertAtCharInc    // insert result at @ character
    bl affichageMess

 
100:                         // standard end of the program
    mov x0,0                 // return code
    mov x8,EXIT              // request to exit program
    svc 0                    // perform the system call
qAdrtablesPoi:         .quad tablesPoi
qAdrszMessLenArea:     .quad szMessLenArea
qAdrsZoneConv:         .quad sZoneConv
qAdrszCarriageReturn:  .quad szCarriageReturn
/********************************************************/
/*        File Include fonctions                        */
/********************************************************/
/* for this file see task include a file in language AArch64 assembly */
.include "../includeARM64.inc"

ABAP

The concept of arrays does not exist in ABAP, instead internal tables are used. Since ABAP Version 7.40 they can be accessed with the common index notation. Note that the index starts at 1 and out of bound access raises an exception. The built-in function "lines" returns the number of records.

report z_array_length.

data(internal_table) = value stringtab( ( `apple` ) ( `orange` ) ).

write: internal_table[ 1 ] , internal_table[ 2 ] , lines( internal_table ).

Output:

apple orange          2

Ada

with Ada.Text_IO;  use Ada.Text_IO;

procedure Array_Length is
   Fruits : constant array (Positive range <>) of access constant String
      := (new String'("orange"),
          new String'("apple"));

begin
   for Fruit of Fruits loop
      Ada.Text_IO.Put (Integer'Image (Fruit'Length));
   end loop;

   Ada.Text_IO.Put_Line ("  Array Size : " & Integer'Image (Fruits'Length));
end Array_Length;

Output:

  6 5  Array Size: 2

ALGOL 68

# UPB returns the upper bound of an array, LWB the lower bound #
[]STRING fruits = ( "apple", "orange" );
print( ( ( UPB fruits - LWB fruits ) + 1, newline ) ) # prints 2 #

AntLang

array: seq["apple"; "orange"]
length[array]
/Works as a one liner: length[seq["apple"; "orange"]]

Apex

System.debug(new String[] { 'apple', 'banana' }.size()); // Prints 2

APL

⍴'apple' 'orange'

Output:

AppleScript

set theList to {"apple", "orange"}
count theList
-- or
length of theList
-- or
number of items in theList

Strictly speaking, 'items in' can be omitted from the last example, since 'number of' does essentially the same as 'length of'. The additional stage of extracting theList's 'items' is inefficient.

Output:

No context or goal is provided for this task – sometimes for example, we may simply want to take the last member of an array, and counting the length to derive an index might well not be the best route.

More generally, we may learn more about AppleScript by defining length() ourselves. There are two basic functional approaches to doing that – we can write a simple recursive definition, or, if we have a higher order fold/reduce function (see Catamorphism) we can derive length() as:

fold (λx n -> 1 + n)  0

on run
    
    set xs to ["alpha", "beta", "gamma", "delta", "epsilon", ¬
        "zeta", "eta", "theta", "iota", "kappa", "lambda", "mu"]
    
    {_length(xs), fold(xs, succ, 0), item 12 of xs, item -1 of xs}
    
    --> {12, 12, "mu", "mu"}
    
end run

-- TWO FUNCTIONAL DEFINITIONS OF LENGTH

-- 1. Recursive definition

on _length(xs)
    if xs is [] then
        0
    else
        1 + _length(rest of xs)
    end if
end _length


-- 2. fold (λx n -> 1 + n)  0

on succ(x)
    1 + x
end succ

--[a] - > (a - > b) - > b - > [b]
on fold(xs, f, startValue)
    script mf
        property lambda : f
    end script
    
    set v to startValue
    repeat with x in xs
        set v to mf's lambda(v, x)
    end repeat
end fold

Output:

{12, 12, "mu", "mu"}

ARM Assembly

Works with: as version Raspberry Pi

/* ARM assembly Raspberry PI  */
/*  program lenAreaString.s   */

/* Constantes    */
.equ STDOUT, 1     @ Linux output console
.equ EXIT,   1     @ Linux syscall
.equ WRITE,  4     @ Linux syscall
/* Initialized data */
.data
szMessLenArea: .ascii "The length of area is : "
sZoneconv:		 .fill 12,1,' '
szCarriageReturn:  .asciz "\n"

/* areas strings  */
szString1:  .asciz "Apples"
szString2:  .asciz "Oranges"
/* pointer items area */
tablesPoi:
ptApples:		.int szString1
ptOranges:   .int szString2
ptVoid:		.int 0

/* UnInitialized data */
.bss 

/*  code section */
.text
.global main 
main:                /* entry of program  */
    push {fp,lr}    /* saves 2 registers */

    ldr r1,iAdrtablesPoi  @ begin pointer table 
    mov r0,#0    @ counter
1:              @ begin loop
    ldr r2,[r1,r0,lsl #2]    @ read string pointer address item r0 (4 bytes by pointer)
    cmp r2,#0                @ is null ?
    addne r0,#1             @ no increment counter
    bne 1b                  @ and loop
 
    ldr r1,iAdrsZoneconv   @ conversion decimal
    bl conversion10S
    ldr r0,iAdrszMessLenArea
    bl affichageMess
	
2:

100:   /* standard end of the program */
    mov r0, #0                  @ return code
    pop {fp,lr}                 @restaur 2 registers
    mov r7, #EXIT              @ request to exit program
    swi 0                       @ perform the system call
iAdrtablesPoi:		.int tablesPoi
iAdrszMessLenArea:  .int szMessLenArea
iAdrsZoneconv:		.int  sZoneconv
iAdrszCarriageReturn:  .int  szCarriageReturn
/******************************************************************/
/*     display text with size calculation                         */ 
/******************************************************************/
/* r0 contains the address of the message */
affichageMess:
    push {fp,lr}    			/* save  registres */ 
    push {r0,r1,r2,r7}    		/* save others registers */
    mov r2,#0   				/* counter length */
1:      	/* loop length calculation */
    ldrb r1,[r0,r2]  			/* read octet start position + index */
    cmp r1,#0       			/* if 0 its over */
    addne r2,r2,#1   			/* else add 1 in the length */
    bne 1b          			/* and loop */
                                /* so here r2 contains the length of the message */
    mov r1,r0        			/* address message in r1 */
    mov r0,#STDOUT      		/* code to write to the standard output Linux */
    mov r7, #WRITE             /* code call system "write" */
    swi #0                      /* call systeme */
    pop {r0,r1,r2,r7}     		/* restaur others registers */
    pop {fp,lr}    				/* restaur des  2 registres */ 
    bx lr	        			/* return  */

/***************************************************/
/*   conversion register signed décimal     */
/***************************************************/
/* r0 contient le registre   */
/* r1 contient l adresse de la zone de conversion */
conversion10S:
    push {r0-r5,lr}    /* save des registres */
    mov r2,r1       /* debut zone stockage */
    mov r5,#'+'     /* par defaut le signe est + */
    cmp r0,#0       /* nombre négatif ? */
    movlt r5,#'-'     /* oui le signe est - */
    mvnlt r0,r0       /* et inversion en valeur positive */
    addlt r0,#1
    mov r4,#10   /* longueur de la zone */
1: /* debut de boucle de conversion */
    bl divisionpar10 /* division  */
    add r1,#48        /* ajout de 48 au reste pour conversion ascii */	
    strb r1,[r2,r4]  /* stockage du byte en début de zone r5 + la position r4 */
    sub r4,r4,#1      /* position précedente */
    cmp r0,#0     
    bne 1b	       /* boucle si quotient different de zéro */
    strb r5,[r2,r4]  /* stockage du signe à la position courante */
    subs r4,r4,#1   /* position précedente */
    blt  100f         /* si r4 < 0  fin  */
    /* sinon il faut completer le debut de la zone avec des blancs */
    mov r3,#' '   /* caractere espace */	
2:
    strb r3,[r2,r4]  /* stockage du byte  */
    subs r4,r4,#1   /* position précedente */
    bge 2b        /* boucle si r4 plus grand ou egal a zero */
100:  /* fin standard de la fonction  */
    pop {r0-r5,lr}   /*restaur desregistres */
    bx lr   

/***************************************************/
/*   division par 10   signé                       */
/* Thanks to http://thinkingeek.com/arm-assembler-raspberry-pi/*  
/* and   http://www.hackersdelight.org/            */
/***************************************************/
/* r0 contient le dividende   */
/* r0 retourne le quotient */	
/* r1 retourne le reste  */
divisionpar10:	
  /* r0 contains the argument to be divided by 10 */
   push {r2-r4}   /* save registers  */
   mov r4,r0 
   ldr r3, .Ls_magic_number_10 /* r1 <- magic_number */
   smull r1, r2, r3, r0   /* r1 <- Lower32Bits(r1*r0). r2 <- Upper32Bits(r1*r0) */
   mov r2, r2, ASR #2     /* r2 <- r2 >> 2 */
   mov r1, r0, LSR #31    /* r1 <- r0 >> 31 */
   add r0, r2, r1         /* r0 <- r2 + r1 */
   add r2,r0,r0, lsl #2   /* r2 <- r0 * 5 */
   sub r1,r4,r2, lsl #1   /* r1 <- r4 - (r2 * 2)  = r4 - (r0 * 10) */
   pop {r2-r4}
   bx lr                  /* leave function */
   bx lr                  /* leave function */
.Ls_magic_number_10: .word 0x66666667

Arturo

fruit: ["apple" "orange"]

print ["array length =" size fruit]

Output:

array length = 2

ATS

#include
"share/atspre_staload.hats"
#include
"share/atspre_staload_libats_ML.hats"

val A0 =
array0_tuple<string>
( "apple", "orange" )
val () =
println!("length(A0) = ", length(A0))

implement main0((*void*)) = ((*void*))

AutoHotkey

MsgBox % ["apple","orange"].MaxIndex()

Output:

AutoIt

Opt('MustDeclareVars',1)	 	; 1 = Variables must be pre-declared.

Local $aArray[2] = ["Apple", "Orange"]
Local $Max = UBound($aArray)
ConsoleWrite("Elements in array: " & $Max & @CRLF)

For $i = 0 To $Max - 1
	ConsoleWrite("aArray[" & $i & "] = '" & $aArray[$i] & "'" & @CRLF)
Next

Output:

Elements in array: 2
aArray[0] = 'Apple'
aArray[1] = 'Orange'

Avail

Using Avail's tuples and the `|_|` method:

|<"Apple", "Orange">|

AWK

The main use of the length()-function is to determine the length of a string.
When used on an array, it returns the number of elements.
Another method to count the elements of the array is by using a variant of for().

# usage:  awk -f arraylen.awk
#
function countElements(array) {
  for( e in array ) {c++}
  return c
}

BEGIN {
  array[1] = "apple"
  array[2] = "orange" 

  print "Array length :", length(array), countElements(array)
  
  print "String length:", array[1], length(array[1])
}

Output:

Array length : 2 2
String length: apple 5

BaCon

BaCon knows three types of arrays, the UBOUND function can query all.

' Static arrays

DECLARE fruit$[] = { "apple", "orange" }
PRINT UBOUND(fruit$)

' Dynamic arrays

DECLARE vegetable$ ARRAY 2
vegetable$[0] = "cabbage"
vegetable$[1] = "spinach"
PRINT UBOUND(vegetable$)

' Associative arrays

DECLARE meat$ ASSOC STRING
meat$("first") = "chicken"
meat$("second") = "pork"
PRINT UBOUND(meat$)

Bash

fruit=("apple" "orange" "lemon")
echo "${#fruit[@]}"

BASIC

DIM X$(1 TO 2)
X$(1) = "apple"
X$(2) = "orange"
PRINT UBOUND(X$) - LBOUND(X$) + 1

Applesoft BASIC

10  DIM A$(2)
20 A$(1) = "ORANGE"
30 A$(2) = "APPLE"
40 N$ = "A$": GOSUB 70: PRINT L$

60  PRINT 
61  DIM A%(19,63,0),A3(4,5)
62 N$ = "A%": GOSUB 70: PRINT L$
63 N$ = "A3": GOSUB 70: PRINT L$
64 N$ = "COMMODORE"
65  GOSUB 70: PRINT L$: END

70 L$ = "":N0 = 0:N1 = 0
71 N0$ =  LEFT$ (N$,1)
72 N1$ =  MID$ (N$,2,2)
73 N1 =  RIGHT$ (N$,1) = "$"
74 N0 =  RIGHT$ (N$,1) = "%"
75  IF N0 THEN N1 = 1
76 I =  LEN (N1$) - N1
77 N1$ =  MID$ (N1$,1,I)
78 A =  ASC (N1$ +  CHR$ (0))
79 N1 = 128 * N1 + A
80 N0 = 128 * N0 +  ASC (N0$)
90  DEF  FN P(A) =  PEEK (A) +  PEEK (A + 1) * 256
100 I =  FN P(109):A =  FN P(107)
110  FOR A = A TO I STEP 0
128  IF  PEEK (A) <  > N0 OR  PEEK (A + 1) <  > N1 THEN A = A +  FN P(A + 2): NEXT A: PRINT "ARRAY "N$" NOT FOUND": STOP 
130 N0 = A + 4
140 N1 = N0 +  FN P(N0) * 2
150 N0 = N0 + 2
160  FOR I = N1 TO N0 STEP  - 2
170 L$ = L$ +  STR$ ( FN P(I))
180 L$ = L$ + " ": NEXT I
190  RETURN

BASIC256

fruta$ = {"apple", "orange", "pear"}
 
print length(fruta$)
print fruta$[?]
print fruta$[1]
end

3
3
orange

Commodore BASIC

Commodore BASIC has no way within the language to query an array for its length, but you can dive into the implementation to get that information. On a C-64 in particular, this works:

Works with: Commodore BASIC version 2.0 on C-64

10 DIM A$(1):REM 1=LAST -> ROOM FOR 2
20 A$(0) = "ORANGE"
30 A$(1) = "APPLE"
40 AT=0:N$="":T=0:L=0:REM DECLARE ALL VARS BEFORE PEEKING
50 AT=PEEK(47)+256*PEEK(48):REM START OF ARRAYS IN MEMORY
60 N$=CHR$(PEEK(AT)AND127)+CHR$(PEEK(AT+1)AND127):REM NAME
70 T=(PEEK(AT) AND 128)*2+(PEEK(AT+1)AND128):REM TYPE
80 IF T=384 THEN N$=N$+"%": REM INTEGER
90 IF T=128 THEN N$=N$+"$": REM STRING
100 L=PEEK(AT+6): REM FIRST INDEX SIZE
110 PRINT N$" HAS"L"ELEMENTS."

Output:

A$ HAS 2 ELEMENTS.

True BASIC

DIM fruta$(2)
READ fruta$(1), fruta$(2)
DATA "apple", "orange"

LET tamano = UBound(fruta$) - LBound(fruta$) + 1

PRINT "La longitud del array fruta$ es" ; tamano
END

Output:

 La longitud del array fruta$ es 2

True BASIC's arrays are not fixed in length and, although True BASIC is a compiled-language, the number of elements can be changed during runtime using such functions as the MAT REDIM (matrix re-dimension) function. Although the starting index of 1 is in implicit, it can be changed by setting the lower and upper bounds (eg. fruit(0 to 3)) when declaring the array. Also, the example below uses the MAT READ function to read in the data elements into the array without having to explicitly list each variable-array index. The example also uses the SIZE function vs the bounds method to determine the length of the array. Finally, in this example the SIZE function was not assigned to a separate variable and instead is used within the PRINT function itself.

DIM fruit$(2) 
MAT READ fruit$ 
DATA "apple", "orange"

PRINT "The length of the array 'fruit$' is "; SIZE(fruit$)
END

Output:

 The length of the array 'fruit$' is 2

Batch File

While batch files don't support arrays in the traditional sense, sets of variables forming somewhat of a pseudo-array are extremely useful. They are usually in the form of %name{number}%. The below code gives an example of how to create an array from a list stored in a variable, and how to acquire the amount of entries in the array.

@echo off

:_main
setlocal enabledelayedexpansion

:: This block of code is putting a list delimitered by spaces into an pseudo-array
:: In practice, this could be its own function _createArray however for the demonstration, it is built in
set colour_list=red yellow blue orange green
set array_entry=0
for %%i in (%colour_list%) do (
  set /a array_entry+=1
  set colours[!array_entry!]=%%i
)

call:_arrayLength colours
echo _arrayLength returned %errorlevel%
pause>nul
exit /b

:: _arrayLength returns the length of the array parsed to it in the errorcode
:_arrayLength
setlocal enabledelayedexpansion

:loop
set /a arrayentry=%arraylength%+1
if "!%1[%arrayentry%]!"=="" exit /b %arraylength%
set /a arraylength+=1
goto loop

Input:

red yellow blue orange green

Output:

_arrayLength returned 5

BBC BASIC

Works with: BBC BASIC for Windows

      DIM array$(1)
      array$() = "apple", "orange"
      PRINT "Number of elements in array = "; DIM(array$(), 1) + 1
      PRINT "Number of bytes in all elements combined = "; SUMLEN(array$())
      END

Output:

Number of elements in array = 2
Number of bytes in all elements combined = 11

Brat

p ["apple", "orange"].length

BQN

≠ gives the length of an array in BQN.

≠ 1‿"a"‿+

Try It!

C

A commonly used solution

C features two kinds of arrays: static (compile-time, fixed size) and dynamic (allocated at runtime).

The length of a dynamic array cannot be acquired from the array itself - its length must be stored elsewhere.

For static arrays:

#include <stdio.h>

int main()
{    
    const char *fruit[2] = { "apples", "oranges" };

    // Acquire the length of the array by dividing the size of all elements (found
    // with sizeof(fruit)) by the size of the first element.

    // Note that since the array elements are pointers to null-terminated character
    // arrays, the size of the first element is actually the size of the pointer
    // type - not the length of the string.

    // This size, regardless of the type being pointed to, is 8 bytes, 4 bytes, or
    // 2 bytes on 64-bit, 32-bit, or 16-bit platforms respectively.
    int length = sizeof(fruit) / sizeof(fruit[0]);

    printf("%d\n", length);

    return 0;
}

A C pre-processor macro may be created for ease of use:

#define ARRAY_LENGTH(A) (sizeof(A) / sizeof(A[0]))

Note that these arrays become pointers when passed as a parameter to a function. Thus, the length of an array parameter may not be required directly - a dedicated length parameter would be required.

Safe solution

The C language uses arrays of a declared size (including variable length arrays, i.e. VLA) and dynamically allocated memory blocks. While they are mostly the same, it is important that the sizeof operator, which returns a number of bytes, behaves quite differently for arrays and for memory pointers.

The problem is that arrays are passed to functions (procedures) via pointers. Even if we define a global variable as an array, after using it as a function argument the appropriate parameter will "forget" what size the array is.

Therefore, an object-oriented technique is used in the solution below. (This is possible even with standard C, i.e. C without ++.) Block of memory in which is stored the array is wrapped in structure and thus the size of the array can be easily stored. It is very convenient. Having defined such "classes" as StringArray, their use is easy and hassle-free. Nevertheless, the C language is not designed for OOP, and therefore C ++ is simply better for these kinds of applications.

Solution

#define _CRT_SECURE_NO_WARNINGS    // turn off panic warnings
#define _CRT_NONSTDC_NO_WARNINGS   // enable old-gold POSIX names in MSVS

#include <stdarg.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <assert.h>


struct StringArray
{
    size_t sizeOfArray;
    size_t numberOfElements;
    char** elements;
};
typedef struct StringArray* StringArray;

StringArray StringArray_new(size_t size)
{
    StringArray this = calloc(1, sizeof(struct StringArray));
    if (this)
    {
        this->elements = calloc(size, sizeof(int));
        if (this->elements)
            this->sizeOfArray = size;
        else
        {
            free(this);
            this = NULL;
        }
    }
    return this;
}

void StringArray_delete(StringArray* ptr_to_this)
{
    assert(ptr_to_this != NULL);
    StringArray this = (*ptr_to_this);
    if (this)
    {
        for (size_t i = 0; i < this->sizeOfArray; i++)
            free(this->elements[i]);
        free(this->elements);
        free(this);
        this = NULL;
    }
}

void StringArray_add(StringArray this, ...)
{
    char* s;
    va_list args;
    va_start(args, this);
    while (this->numberOfElements < this->sizeOfArray && (s = va_arg(args, char*)))
        this->elements[this->numberOfElements++] = strdup(s);
    va_end(args);
}


int main(int argc, char* argv[])
{
    StringArray a = StringArray_new(10);
    StringArray_add(a, "apple", "orange", NULL);

    printf(
        "There are %d elements in an array with a capacity of %d elements:\n\n",
        a->numberOfElements, a->sizeOfArray);

    for (size_t i = 0; i < a->numberOfElements; i++)
        printf("    the element %d is the string \"%s\"\n", i, a->elements[i]);

    StringArray_delete(&a);

    return EXIT_SUCCESS;
}

Output:

There are 2 elements in an array with a capacity of 10 elements:

    the element 0 is the string "apple"
    the element 1 is the string "orange"

An example why sizeof(A)/sizeof(E) may be a bad idea in C

#define _CRT_SECURE_NO_WARNINGS    // turn off panic warnings
#define _CRT_NONSTDC_NO_WARNINGS   // enable old-gold POSIX names in MSVS

#include <stdio.h>
#include <stdlib.h>
#include <time.h>

#define N 10

// Fixed size global arrays

static const int scGlobal[N];
const int cGlobal[N];
static int sGlobal[N];
int Global[N];

#define TEST(A, N)                                                             \
 do {                                                                          \
    puts("");                                                                  \
    printf("directly called:          sizeof(%8s) = %2d,  length = %2d,  %s\n",\
        #A,                                                                    \
        sizeof(A),                                                             \
        sizeof(A) / sizeof(int),                                               \
        sizeof(A) / sizeof(int) == N ? "pass" : "fail");                       \
                                                                               \
    test1(#A, A, N);                                                           \
    test2(#A, A, N);                                                           \
    test3(#A, A, N);                                                           \
} while (0);

void test1(char* name, int* A, int n)
{
    printf("as parameter int* A:      sizeof(%8s) = %2d,  length = %2d,  %s\n",
        name,
        sizeof(A),
        sizeof(A) / sizeof(int),
        sizeof(A) / sizeof(int) == n ? "pass" : "fail");
}

void test2(char* name, int A[], int n)
{
    printf("as parameter int A[]:     sizeof(%8s) = %2d,  length = %2d,  %s\n", 
        name, 
        sizeof(A), 
        sizeof(A) / sizeof(int),
        sizeof(A) / sizeof(int) == n ? "pass" : "fail");
}

void test3(char* name, int A[10], int n)
{
    printf("as parameter int A[10]:   sizeof(%8s) = %2d,  length = %2d,  %s\n",
        name,
        sizeof(A),
        sizeof(A) / sizeof(int),
        sizeof(A) / sizeof(int) == n ? "pass" : "fail");
}


int main(int argc, char argv[])
{
    // Fixed size local arrays (defined inside curly braces block)

    static const int scLocal[N];
    const int cLocal[N];
    static int sLocal[N];
    auto int aLocal[N];
    int Local[N];

    // Fixed size VLA arrays can/should be used instead dynamically alocated 
    // blocks. VLA has not implemented in Microsoft Visual Studio C.

    srand(time(NULL));
    int n = N + rand() % 2; // the value of n is unknow in the compile time?

#ifndef _MSC_VER
    int vlaLocal[n];
#endif

    // Memory blocks as ersatz arrays. This is not all possible ways to allocate
    // memory. There are other functions, like LocalAlloc, HeapAlloc, sbreak...
    // Don't use alloca in any serious program - this function is really bad
    // choice - it can corrupt the program stack and generate a stack overflow.

    int* mBlock = (int*)malloc(n * sizeof(int));
    int* cBlock = (int*)calloc(n, sizeof(int));
    int* aBlock = (int*)_alloca(n * sizeof(int)); // don't use in your programs!

    TEST(scGlobal, N);
    TEST(cGlobal, N);
    TEST(sGlobal, N);
    TEST(Global, N);

    TEST(scLocal, N);
    TEST(cLocal, N);
    TEST(sLocal, N);
    TEST(aLocal, N);
    TEST(Local, N);

#ifndef _MSC_VER
    TEST(vlaLocal, n);
#endif

    TEST(mBlock, N);
    TEST(cBlock, N);
    TEST(aBlock, N);

    free(mBlock, N);
    free(cBlock, N);
    // free must not be called on aBlock

    return 0;
}

As we can see the sizeof(ArrayType)/sizeof(ElementType) approach mostly fail.

Output:

directly called:          sizeof(scGlobal) = 40,  length = 10,  pass
as parameter int* A:      sizeof(scGlobal) =  4,  length =  1,  fail
as parameter int A[]:     sizeof(scGlobal) =  4,  length =  1,  fail
as parameter int A[10]:   sizeof(scGlobal) =  4,  length =  1,  fail

directly called:          sizeof( cGlobal) = 40,  length = 10,  pass
as parameter int* A:      sizeof( cGlobal) =  4,  length =  1,  fail
as parameter int A[]:     sizeof( cGlobal) =  4,  length =  1,  fail
as parameter int A[10]:   sizeof( cGlobal) =  4,  length =  1,  fail

directly called:          sizeof( sGlobal) = 40,  length = 10,  pass
as parameter int* A:      sizeof( sGlobal) =  4,  length =  1,  fail
as parameter int A[]:     sizeof( sGlobal) =  4,  length =  1,  fail
as parameter int A[10]:   sizeof( sGlobal) =  4,  length =  1,  fail

directly called:          sizeof(  Global) = 40,  length = 10,  pass
as parameter int* A:      sizeof(  Global) =  4,  length =  1,  fail
as parameter int A[]:     sizeof(  Global) =  4,  length =  1,  fail
as parameter int A[10]:   sizeof(  Global) =  4,  length =  1,  fail

directly called:          sizeof( scLocal) = 40,  length = 10,  pass
as parameter int* A:      sizeof( scLocal) =  4,  length =  1,  fail
as parameter int A[]:     sizeof( scLocal) =  4,  length =  1,  fail
as parameter int A[10]:   sizeof( scLocal) =  4,  length =  1,  fail

directly called:          sizeof(  cLocal) = 40,  length = 10,  pass
as parameter int* A:      sizeof(  cLocal) =  4,  length =  1,  fail
as parameter int A[]:     sizeof(  cLocal) =  4,  length =  1,  fail
as parameter int A[10]:   sizeof(  cLocal) =  4,  length =  1,  fail

directly called:          sizeof(  sLocal) = 40,  length = 10,  pass
as parameter int* A:      sizeof(  sLocal) =  4,  length =  1,  fail
as parameter int A[]:     sizeof(  sLocal) =  4,  length =  1,  fail
as parameter int A[10]:   sizeof(  sLocal) =  4,  length =  1,  fail

directly called:          sizeof(  aLocal) = 40,  length = 10,  pass
as parameter int* A:      sizeof(  aLocal) =  4,  length =  1,  fail
as parameter int A[]:     sizeof(  aLocal) =  4,  length =  1,  fail
as parameter int A[10]:   sizeof(  aLocal) =  4,  length =  1,  fail

directly called:          sizeof(   Local) = 40,  length = 10,  pass
as parameter int* A:      sizeof(   Local) =  4,  length =  1,  fail
as parameter int A[]:     sizeof(   Local) =  4,  length =  1,  fail
as parameter int A[10]:   sizeof(   Local) =  4,  length =  1,  fail

directly called:          sizeof(  mBlock) =  4,  length =  1,  fail
as parameter int* A:      sizeof(  mBlock) =  4,  length =  1,  fail
as parameter int A[]:     sizeof(  mBlock) =  4,  length =  1,  fail
as parameter int A[10]:   sizeof(  mBlock) =  4,  length =  1,  fail

directly called:          sizeof(  cBlock) =  4,  length =  1,  fail
as parameter int* A:      sizeof(  cBlock) =  4,  length =  1,  fail
as parameter int A[]:     sizeof(  cBlock) =  4,  length =  1,  fail
as parameter int A[10]:   sizeof(  cBlock) =  4,  length =  1,  fail

directly called:          sizeof(  aBlock) =  4,  length =  1,  fail
as parameter int* A:      sizeof(  aBlock) =  4,  length =  1,  fail
as parameter int A[]:     sizeof(  aBlock) =  4,  length =  1,  fail
as parameter int A[10]:   sizeof(  aBlock) =  4,  length =  1,  fail

C#

using System;

class Program
{
    public static void Main()
    {
        var fruit = new[] { "apple", "orange" };
        Console.WriteLine(fruit.Length);
    }
}

Note that any of the following array declarations could be used:

var fruit = new[] { "apple", "orange" };
var fruit = new string[] { "apple", "orange" };
string[] fruit = new[] { "apple", "orange" };
string[] fruit = new string[] { "apple", "orange" };
string[] fruit = { "apple", "orange" };

A shorter variant could also have been used:

using static System.Console;

class Program 
{
    public static void Main()
    {
        WriteLine(new[] { "apples", "oranges" }.Length);
    }
}

C++

C++ follows the same rules as C regarding static and dynamic arrays.

However, C++ has an additional std::array type (amongst other collections) in its standard library:

#include <array>
#include <iostream>
#include <string>

int main() 
{
    std::array<std::string, 2> fruit { "apples", "oranges" };
    std::cout << fruit.size();
    return 0;
}

Note that char* or const char* could have been used instead of std::string.

In addition to the std::array type, the C++ standard library also provides dynamically-sized containers to hold arbitrary objects. These all support similar interfaces, though their implementations have different performance characteristics.

    std::vector<std::string> fruitV({ "apples", "oranges" });
    std::list<std::string> fruitL({ "apples", "oranges" });
    std::deque<std::string> fruitD({ "apples", "oranges" });
    std::cout << fruitV.size() << fruitL.size() << fruitD.size() << std::endl;

Of these, vector is probably the most widely used.

Ceylon

shared void run() {
	value array = ["apple", "orange"];
	print(array.size);
}

Clipper/XBase++

/*
 * nizchka: March - 2016
 * This is a Clipper/XBase++ of RosettaCode Array_Length  
 */

PROCEDURE MAIN()
        LOCAL FRUIT := { "apples","oranges" }

        ? LEN(FRUIT)
RETURN

Outputs:

nizchka 23:27, 16 March 2016 (UTC)

Clojure

; using count:
(count ["apple" "orange"])

; OR alength if using Java arrays:
(alength (into-array ["apple" "orange"]))

COBOL

Arrays in COBOL are usually referred to as tables. Tables can have fixed or variable (with known maximum) allocations, using a syntax of OCCURS DEPENDING ON. The value of the ODO identifier is the number of active elements in the table.

       identification division.
       program-id. array-length.

       environment division.
       configuration section.
       repository.
           function all intrinsic.

       data division.
       working-storage section.
       01 table-one.
          05 str-field pic x(7) occurs 0 to 5 depending on t1.

       77 t1           pic 99.

       procedure division.
       array-length-main.
       perform initialize-table
       perform display-table-info
       goback.

       initialize-table.
           move 1 to t1
           move "apples" to str-field(t1)

           add 1 to t1
           move "oranges" to str-field(t1).

      *> add an extra element and then retract table size
           add 1 to t1
           move "bananas" to str-field(t1).
           subtract 1 from t1
       .

       display-table-info.
           display "Elements: " t1 ", using " length(table-one) " bytes"
           display table-one
       .

       end program array-length.

Output:

$ cobc -xjd array-length.cob
Elements: 02, using 000000014 bytes
apples oranges

ColdFusion

<cfset testArray = ["apple","orange"]>
<cfoutput>Array Length = #ArrayLen(testArray)#</cfoutput>

Outputs:

Array Length = 2

Mike Knapp 15:57, 26 May 2016 (UTC)

Common Lisp

(print (length #("apple" "orange")))

Alternate solution

I use Allegro CL 10.1

;; Project : Array length

(setf my-array (make-array '(2)))
(setf (aref my-array 0) "apple")
(setf (aref my-array 1) "orange")
(format t "~a" "length of my-array: ")
(length my-array)
(terpri)

Output:

length of my-array: 2

Component Pascal

Works with: BlackBox Component Builder

MODULE AryLen;
IMPORT StdLog;

TYPE
	String = POINTER TO ARRAY OF CHAR;
VAR
	a: ARRAY 16 OF String;
	
PROCEDURE NewString(s: ARRAY OF CHAR): String;
VAR
	str: String;
BEGIN
	NEW(str,LEN(s$) + 1);str^ := s$; RETURN str
END NewString;

PROCEDURE Length(a: ARRAY OF String): INTEGER;
VAR
	i: INTEGER;
BEGIN
	i := 0;
	WHILE a[i] # NIL DO INC(i) END;
	RETURN i
END Length;

PROCEDURE Do*;
BEGIN
	a[0] := NewString("Apple");
	a[1] := NewString("Orange");
	StdLog.String("Length:> ");StdLog.Int(Length(a));StdLog.Ln
END Do;

END AryLen.

Execute: ^Q AryLen.Do

Output:

Length:>  2

Crystal

puts ["apple", "orange"].size

Output:

D

import std.stdio;

int main()
{
    auto fruit = ["apple", "orange"];
    fruit.length.writeln;
    return 0;
}

Or a somewhat shorter...

import std.stdio;

void main()
{
    ["apple", "orange"].length.writeln;
}

Dart

arrLength(arr) {
  return arr.length;
}

main() {
  var fruits = ['apple', 'orange'];
  print(arrLength(fruits));
}

DataWeave

var arr = ["apple", "orange"]
sizeOf(arr)

Delphi

   showmessage(  length(['a','b','c']).ToString );

Diego

set_namespace(rosettacode)_me();

me_msg()_array()_values(apple,orange)_length();
    
reset_namespace[];

Output:

Dragon

select "std" 

a = ["apple","orange"]
b = length(a) 

show b

Dyalect

var xs = ["apple", "orange"]
print(xs.Length())

EasyLang

<lang>fruit$[] = [ "apples" "oranges" ] print len fruit$[]</syntaxhighlight>

EchoLisp

(length '("apple" "orange")) ;; list
   → 2
(vector-length #("apple" "orange")) ;; vector
   → 2

Ela

length [1..10]

Elena

ELENA 5.0 :

    var array := new string[]{"apple", "orange"};
    var length := array.Length;

Elixir

iex(1)> length( ["apple", "orange"] )          # List
2
iex(2)> tuple_size( {"apple", "orange"} )      # Tuple
2

Elm

import Array
import Html

main : Html.Html
main = 
    ["apple", "orange"]
      |> Array.fromList
      |> Array.length
      |> Basics.toString
      |> Html.text

Emacs Lisp

(length ["apple" "orange"])
=> 2

length also accepts a list or a string.

Erlang

1> length(["apple", "orange"]).     %using a list
2
1> tuple_size({"apple", "orange"}). %using a tuple
2

Euphoria

sequence s = {"apple","orange",2.95} -- Euphoria doesn't care what you put in a sequence

? length(s)

3 -- three objects

? length(s[1])

5 -- apple has 5 characters

? length(s[1][$])

1 -- 'e' is an atomic value


? length(s[$])

1 -- 2.95 is an atomic value

F#

[|1;2;3|].Length |> printfn "%i"

Or:

[|1;2;3|] |> Array.length |> printfn "%i"

Factor

{ "apple" "orange" } length

Forth

The philosophy of Chuck Moore, the creator of Forth was that he did not want to write code for something he may never use. His solution was to distill his language into a large set of very simple routines that control the hardware directly. This demonstration must build "arrays" from scratch. In Forth, like in Assembler, you can do this any way you want. This demonstration adds new words to Forth that make a syntax to create simple variable length string arrays. Each string is a counted string with no trailing zero.

The code is commented to explain what is going on for those unfamiliar with Forth.

<lang>: STRING, ( caddr len -- ) \ Allocate space & compile string into memory

            HERE  OVER CHAR+  ALLOT  PLACE ;

" ( -- ) [CHAR] " PARSE STRING, ; \ Parse input to " and compile to memory

\ Array delimiter words

{ ALIGN 0 C, ; \ Compile 0 byte start/end of array

} ALIGN 0 C, ;

\ String array words

{NEXT} ( str -- next_str) \ Iterate to next string

          COUNT + ;

{NTH} ( n array_addr -- str) \ Returns address of the Nth item in the array

          SWAP 0 DO {NEXT} LOOP ;

{LEN} ( array_addr -- n) \ count strings in the array

         0 >R                      \ Counter on Rstack
         {NEXT}
         BEGIN
            DUP C@                 \ Fetch length byte
         WHILE                     \ While true
            R> 1+ >R               \ Inc. counter
            {NEXT}
         REPEAT
         DROP
         R> ;      \ return counter to data stack </syntaxhighlight>

Test code at Forth console

CREATE Q { " Apples" " Oranges" }   q {len} . 2  ok

Fortran

Early fortrans offered no protocol for ascertaining the length (or dimensionality) of arrays, though the compiler has this information. Thus a statement such as PRINT A would print all the elements of a variable A according to its definition. A subprogram that received a parameter would have no access to these details, so its parameter might be declared as A(12345) simply to signify that it was an array (rather than an ordinary variable) and the programmer would rely on other data to know the upper bound to employ, for instance via an additional parameter. Any mistakes would cause crashes! On the other hand, with heavy computational tasks, it was common to take advantage of the opportunities. Thus, a subprogram might regard its array parameter as one-dimensional even though the actual parameter was not. Carefully-programmed routines might thusly process a sequence of elements via 1-D indexing, far faster than the 2-D or higher order indexing of the original. Success at this game required understanding how array elements were arranged in multidimensional arrays.

Later fortrans allowed A(*) to signify an array parameter of unstated upper bound, but there was still a problem with higher dimensions. All but the last dimension has to be stated correctly if a multi-dimensional array parameter is to be indexed correctly - Fortran stores array elements in column-major order.

With Fortran 90, a new protocol was introduced, whereby the parameter might be declared as A(:) signifying an array of one dimension, of bounds unstated. A 2-D array would have A(:,:) and so on. Further, arrays could have arbitrary lower bounds as well, as in A(-7:12) but if no colon appeared for a dimension, the lower bound would be assumed to be one so A(2) means an array of two elements, as before. And as before, in a subprogram a bound could be explicitly stated, perhaps via an explicit parameter such as N, but now with the : scheme, the compiler is passing secret additional parameters to the subprogram giving the bounds of the array, and these can be accessed via the library functions LBOUND and UBOUND. For multi-dimensional arrays there are multiple bounds, and an invocation might be UBOUND(A,DIM = 2) but in the example only a one-dimensional array is involved. These facilities are available only if the new MODULE protocol is employed.

The task is in terms of an array holding the texts "Apple" and "Orange", so a CHARACTER*6 element size will do; the subprogram receives yet another secret parameter specifying the size of CHARACTER parameters. This size can be accessed via the LEN function, and, since in principle the index span is arbitrary, no constant index is sure to be a valid index of some single element: thus the LBOUND function is used to finger one that is.

For a simple example, the WRITE(6,*) suffices: write to standard output (the 6), in free-format (the *).

      MODULE EXAMPLE
       CONTAINS
        SUBROUTINE ABOUND(A)
         CHARACTER*(*) A(:)	!One dimensional array, unspecified bounds.
          WRITE (6,*) "Lower bound",LBOUND(A),", Upper bound",UBOUND(A)
          WRITE (6,*) "Element size",LEN(A(LBOUND(A)))
          WRITE (6,*) A
        END SUBROUTINE ABOUND
      END MODULE EXAMPLE

      PROGRAM SHOWBOUNDS
       USE EXAMPLE
       CHARACTER*6 ARRAY(-1:1)
        ARRAY(-1) = "Apple"
        ARRAY(0) = "Orange"
        ARRAY(1) = ""
        CALL ABOUND(ARRAY)
        WRITE (6,*) "But, when it is at home..."
        WRITE (6,*) "L. bound",LBOUND(ARRAY),", U. bound",UBOUND(ARRAY)
      END

Output:

Lower bound           1 , Upper bound           3
Element size           6
Apple Orange
But, when it is at home...
L. bound          -1 , U. bound           1

Notice that the subprogram sees the array as an old-style array starting with index one! If it is to work with a lower bound other than one, the declaration in the subprogram must state it, perhaps as A(-1:) or as A(START:), etc. The upper bound remains unspecified, and with that declaration, UBOUND returns 1 instead of 3, corresponding to the shift. Thus, UBOUND returns not the actual upper bound of the array parameter (as supplied) but the upper bound relative to the lower bound in use in the subprogram so that UBOUND - LBOUND + 1 does give the number of elements.

If in the subprogram the bounds are fixed (say as A(-1:6)) then a CALL ABOUND(ARRAY) may provoke a compiler complaint if ARRAY is not a suitable size.

FreeBASIC

' FB 1.05.0 Win64

Dim fruit(1) As String = {"apple", "orange"}
Dim length As Integer = UBound(fruit) - LBound(fruit) + 1
Print "The length of the fruit array is"; length
Print
Print "Press any key to quit the program"
Sleep

Output:

The length of the fruit array is 2

Frink

a = ["apple", "orange"]
println[length[a]]

FurryScript

THE_LIST( <apple> <orange> )
COUNT[ 0 SW ~| COUNT_STEP# 0 SW SU ]
COUNT_STEP[ DR 1 SU ]

`THE_LIST COUNT# +<>

Futhark

This example may be incorrect due to a recent change in the task requirements or a lack of testing. Please verify it and remove this message. If the example does not match the requirements or does not work, replace this message with Template:incorrect or fix the code yourself.

The shape builtin returns the shape of an array as an array of integers. The length is element 0 of the shape:

fun length(as: []int): int = (shape as)[0]

FutureBasic

NSUInteger count = fn ArrayCount( array ). Example:

window 1
print fn ArrayCount( @[@"apple",@"orange",@"cherry",@"grape",@"lemon"] )
HandleEvents

Output:

Fōrmulæ

Fōrmulæ programs are not textual, visualization/edition of programs is done showing/manipulating structures but not text. Moreover, there can be multiple visual representations of the same program. Even though it is possible to have textual representation —i.e. XML, JSON— they are intended for storage and transfer purposes more than visualization and edition.

Programs in Fōrmulæ are created/edited online in its website, However they run on execution servers. By default remote servers are used, but they are limited in memory and processing power, since they are intended for demonstration and casual use. A local server can be downloaded and installed, it has no limitations (it runs in your own computer). Because of that, example programs can be fully visualized and edite/d, but some of them will not run if they require a moderate or heavy computation/memory resources, and no local server is being used.

In this page you can see the program(s) related to this task and their results.

Gambas

Click this link to run this code

Public Sub Main()
Dim siList As Short[] = [1, 2, 3, 4, 5, 6, 7, 8, 9, 0]

Print siList.Count

End

Output:

Genie

[indent=4]
/* Array length, in Genie */
init
    arr:array of string = {"apple", "orange"}
    stdout.printf("%d ", arr.length)
    print arr[1]

Output:

prompt$ valac array_length.gs
prompt$ ./array_length
2 orange

Go

package main

import "fmt"

func main() {
	arr := [...]string{"apple", "orange", "pear"}

	fmt.Printf("Length of %v is %v.\n", arr, len(arr))
}

Output:

Length of [apple orange pear] is 3.

Groovy

def fruits = ['apple','orange']
println fruits.size()

Harbour

LOCAL aFruits := {"apple", "orange"}
Qout( Len( aFruits ) ) // --> 2

Haskell

-- [[Char]] -> Int
length ["apple", "orange"]

hexiscript

let a arr 2
let a[0] "apple"
let a[1] "orange"
println len a

Hoon

|=  arr=(list *)  (lent arr)

i

main: print(#["apple", "orange"])

Icon and Unicon

Icon, and therefore Unicon, includes a prefix size operator, star *. This operator can be applied to just about any data type or data structure.

write(*["apple", "orange"])

Idris

length ["apple", "orange"]

J

Tally (#) returns the length of the leading dimension of an array (or 1 if the array has no dimensions). Shape Of ($) returns the length of each dimension of an array.

   # 'apple';'orange'
2
   $ 'apple';'orange'
2

For the list array example given, the result appears to be the same. The difference is that the result of Tally is a scalar (array of 0 dimensions) whereas the result of Shape Of is a list (1 dimensional array), of length 1 in this case.

   $#'apple';'orange'

   $$'apple';'orange'
1

This might be a clearer concept with a few more examples. Here's an array with two dimensions:

   >'apple';'orange'
apple 
orange
   $>'apple';'orange'
2 6
   #>'apple';'orange'
2

And, here's an array with no dimensions: <lang> 9001 9001

  #9001

1

  $9001

</syntaxhighlight> You can count the number of dimensions of an array (the length of the list of lengths) using #$array:

   #$9001
0
   #$'apple';'orange'
1
   #$>'apple';'orange'
2

Janet

(def our-array @["apple" "orange"])
(length our-array)

Output:

Java

public class ArrayLength {
    public static void main(String[] args) {
        System.out.println(new String[]{"apple", "orange"}.length);
    }
}

JavaScript

console.log(['apple', 'orange'].length);

However, determining the length of a list, array, or collection may simply be the wrong thing to do.

If, for example, the actual task (undefined here, unfortunately) requires retrieving the final item, while it is perfectly possible to write last in terms of length

function last(lst) {
    return lst[lst.length - 1];
}

using length has the disadvantage that it leaves last simply undefined for an empty list.

We might do better to drop the narrow focus on length, and instead use a fold (reduce, in JS terms) which can return a default value of some kind.

function last(lst) {
    return lst.reduce(function (a, x) {
        return x;
    }, null);
}

Alternatively, rather than scanning the entire list to simply get the final value, it might sometimes be better to test the length:

function last(list, defaultValue) {
   return list.length ?list[list.length-1] :defaultValue;
}

Or use other built-in functions – this, for example, seems fairly clear, and is already 100+ times faster than unoptimised tail recursion in ES5 (testing with a list of 1000 elements):

function last(list, defaultValue) {
    return list.slice(-1)[0] || defaultValue;
}

jq

["apple","orange"] | length

Output:

Note that the length filter is polymorphic, so for example the empty string (""), the empty list ([]), and null all have length 0.

Jsish

/* Array length, in jsish */
var arr = new Array('apple', 'orange');
puts(arr.length);
puts(arr[1]);

Output:

prompt$ jsish arrayLength.jsi
2
orange

Julia

a = ["apple","orange"]
length(a)

Klingphix

include ..\Utilitys.tlhy

( "apple" "orange" ) len print

" " input

Output:

Klong

#["apple" "orange"]

Kotlin

fun main(args: Array<String>) {
    println(arrayOf("apple", "orange").size)
}

Lambdatalk

{A.length {A.new 1 2 3}}
-> 3

Latitude

In Latitude, length and size are synonymous and will both retrieve the size of a collection.

println: ["apple", "orange"] length.

Liberty BASIC

When a one or two dimensional array, A$, with subscript(s) of 10 or less is referenced (either by assigning or reading), the compiler does an implicit DIM A$(10) or DIM A$(10,10). Before referencing an array with any subscript numbered higher than 10, or arrays of three dimensions or more, the programmer must first issue an explicit DIM statement.

There is no function in Liberty Basic to directly read the size of an array. This program uses error trapping loops to, first, determine the number of dimensions of the array. Then, second, again uses error trapping loops to determine the number of elements in each dimension. Finally, it prints the DIM statement that was used to define the array.

I suppose the implicit DIM feature makes it a bit quicker to write short, simple programs. One or two dimension arrays may be resized with REDIM. Three dimension or more arrays can not be resized. All arrays may be cleared with REDIM. Keep in mind that A$(n) and A$(n,m) are the same array. You must refer to it with the correct arguments or get an error.

NOTE -- This program runs only under LB Booster version 3.05 or higher because of arrays with more than two dimensions, passed array names to functions and subroutines as a parameter, and structured error trapping syntax. Get the LBB compiler here: http://lbbooster.com/

Works with: LB Booster

FruitList$(0)="apple" 'assign 2 cells of a list array
FruitList$(1)="orange"
dimension=dimension(FruitList$()) 'first get the dimension of the array
if dimension>3 then
    print "Sorry, program only written for array dimensions of 3 or less."
    end 
end if
call elements FruitList$(), dimension 'next get the size of each dimension
end

function dimension(array$())
    for dimension=1 to 4
        select case dimension
            case 1
                try: x$=array$(0)
                catch: goto [TryNext]
                end try
                exit for
            case 2
                try: x$=array$(0,0)
                catch: goto [TryNext]
                end try
                exit for
            case 3
                try: x$=array$(0,0,0)
                catch: goto [TryNext]
                end try
                exit for
            case 4
                exit for
        end select
    [TryNext]
    next dimension
    if dimension<4 then print "array dimension = "; dimension
    ArraySize(0)=dimension
end function

sub elements array$(), dimension
    select case dimension
        case 1
            try
                do
                    x$=array$(a)
                    a+=1
                loop
            catch: elements=a
            end try
            ArraySize(1)=elements-1
            print "dimension 1 has "; elements; " elements (cells), "_
                    "numbered 0 to "; ArraySize(1)
        case 2
            try
                do
                    x$=array$(a,0)
                    a+=1
                loop
            catch: elements=a
            end try
            ArraySize(1)=elements-1
            print "dimension 1 has "; elements; " elements (cells), "_
                    "numbered 0 to "; ArraySize(1)
            elements=0
            try
                do
                    x$=array$(0,b)
                    b+=1
                loop
            catch: elements=b
            end try            ArraySize(2)=elements-1
            print "dimension 2 has "; elements; " elements (cells), "_
                    "numbered 0 to "; ArraySize(2)
        case 3
            try
                do
                    x$=array$(a,0,0)
                    a+=1
                loop
            catch: elements=a
            end try
            ArraySize(1)=elements-1
            print "dimension 1 has "; elements; " elements (cells), "_
                    "numbered 0 to "; ArraySize(1)
            elements=0
            try
                do
                    x$=array$(0,b,0)
                    b+=1
                loop
            catch: elements=b
            end try
            ArraySize(2)=elements-1
            print "dimension 2 has "; elements; " elements (cells), "_
                    "numbered 0 to "; ArraySize(2)
            elements=0
            try
                do
                    x$=array$(0,0,c)
                    c+=1
                loop
            catch: elements=c
            end try
            ArraySize(3)=elements-1
            print "dimension 3 has "; elements; " elements (cells), "_
                    "numbered 0 to "; ArraySize(3)
    end select
   'print the explicit or implied DIMension statement for this array 
    print "DIM array$("; a-1;
    if b>0 then print ","; b-1;
    if c>0 then print ","; c-1;
    print ")" 
end sub

Output:

array dimension = 1
dimension 1 has 11 elements (cells), numbered 0 to 10
DIM array$(10)

LIL

LIL does not use arrays, but indexed lists. The builtin count command returns the item count in a list. The length command returns the length of the list after string conversion.

# Array length, in LIL
set a [list "apple"]
append a "orange"
print [count $a]
print [index $a 1]

Output:

prompt$ lil arrayLength.lil
2
orange

Limbo

implement Command;

include "sys.m";
sys: Sys;

include "draw.m";

include "sh.m";

init(nil: ref Draw->Context, nil: list of string)
{
	sys = load Sys Sys->PATH;

	a := array[] of {"apple", "orange"};
	sys->print("length of a: %d\n", len a);
}

Lingo

fruits = ["apple", "orange"]
put fruits.count
-- 2

Little

string fruit[] = {"apples", "oranges"};
puts(length(fruit));

LiveCode

put "apple","orange" into fruit
split fruit using comma
answer the number of elements of fruit

Lua

-- For tables as simple arrays, use the # operator:
fruits = {"apple", "orange"}
print(#fruits)

-- Note the # symbol does not work for non-integer-indexed tables:
fruits = {fruit1 = "apple", fruit2 = "orange"}
print(#fruits)

-- For this you can use this short function:
function size (tab)
  local count = 0
  for k, v in pairs(tab) do
    count = count + 1
  end
  return count
end

print(size(fruits))

Output:

2
0
2

M2000 Interpreter

\\ A is a pointer to array
A=("Apple", "Orange")
Print  Len(A)=2  ' True
Print Dimension(A, 0)  ' LBound (0 or 1), here 0
Print Dimension(A)  ' No of Dimensions 1
Print Dimension(A, 1) ' for 1 dimension array this is also Length=2
\\ A$( ) is an Array (not a pointer to array)
Dim Base 1, A$(2)
A$(1)="Apple", "Orange"
Print Dimension(A$(), 0)  ' LBound (0 or 1), here 1
Print Dimension(A$())  ' No of Dimensions 1
Print Dimension(A$(), 1) ' for 1 dimension array this is also Length=2
Link A to B$()  ' B$() is a reference to A
Print B$(0)=A$(1)
Print B$(1)=A$(2)
Dim C$()
\\ C$() get a copy of B$()
C$()=B$()
Print C$()  ' prints Apple Orange
\\ An array can link to a new name as reference, and can change major type
\\ here A$() get A() so we can read/store numbers and read/store strings in same array
\\ using two names
Link A$() to A()
\\ An array pointer can point to another array
A=A()
Print Dimension(A, 0)  ' LBound (0 or 1), here 1 (was 0)
\\ Because B$() is reference of A:
Print Dimension(B$(), 0)  ' LBound (0 or 1), here 1 (was 0)
Print B$(1)=A$(1)
Print B$(2)=A$(2)
Print Dimension(C$(), 0)  ' LBound (0 or 1), here 0
\\ change base preserve items
Dim Base 1, C$(Dimension(C$(), 1))
Print Dimension(C$(), 0)  ' LBound (0 or 1), here 1 (was 0)
Print C$()  ' prints Apple Orange
Print Len(C$()) ' Len return all items of an array - can be 0
Dim K(1,1,1,1,1,1)  ' Maximum 10 dimensions
Print Len(K()=1 ' True

Maple

a := Array(["apple", "orange"]);
numelems(a);

Output:

a := [ "apple" "orange" ]
2

Mathematica/Wolfram Language

Length[{"apple", "orange"}]

MATLAB / Octave

length({'apple', 'orange'})

For arrays with more than one dimension, length reports the length of the larges dimension. The number of elements in a multi-dimensional array can be obtained with numel.

numel({'apple', 'orange'; 'pear', 'banana'})

Modula-3

MODULE ArrayLength EXPORTS Main;

IMPORT IO;

VAR
     Arr:ARRAY[1..2] OF TEXT :=
			     ARRAY[1..2] OF TEXT{"apples", "oranges"};
BEGIN
     IO.PutInt(NUMBER(Arr));
END ArrayLength.

Mercury

:- module array_length.
:- interface.

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

:- implementation.

:- import_module array, list.

main(!IO) :-
    Array = array(["apples", "oranges"]),
    io.write_int(size(Array), !IO).

min

Works with: min version 0.19.3

("apple" "orange") size print

Output:

MiniScript

fruits = ["apple", "orange"]
print fruits.len

MiniZinc

array[int] of int: arr = [1,2,3];
var int: size = length(arr);

solve satisfy;

output [show(size),"\n"];

Nanoquery

fruit = array(2)
fruit[0] = "apple"
fruit[1] = "orange"
println len(fruit)

// outputs 2

Neko

var fruit = $array("apple", "orange");

$print($asize(fruit));

NewLISP

(println (length '("apple" "orange")))

; Nehal-Singhal 2018-05-25
(length '(apple orange))

NGS

echo(len(['apple', 'orange']))
# same
echo(['apple', 'orange'].len())

Nim

let fruit = ["apple", "orange"]
echo "The length of the fruit array is ", len(fruit)

Output:

The length of the fruit array is 2

Oberon-2

Works with: oo2c

MODULE ArrayLength;
IMPORT 
  Strings,
  Out;
TYPE
  String = POINTER TO ARRAY OF CHAR;
VAR
  a: ARRAY 16 OF String;

PROCEDURE NewString(s: ARRAY OF CHAR): String;
VAR
  str: String;
BEGIN
  NEW(str,Strings.Length(s) + 1);COPY(s,str^);
  RETURN str
END NewString;

PROCEDURE Length(a: ARRAY OF String): LONGINT;
VAR
  i: LONGINT;
BEGIN
  i := 0;
  WHILE (a[i] # NIL) DO INC(i) END;
  RETURN i;
END Length;

BEGIN
  a[0] := NewString("apple");
  a[1] := NewString("orange");
  Out.String("length: ");Out.Int(Length(a),0);Out.Ln
END ArrayLength.

Output:

length: 2

Objeck

class Test {
  function : Main(args : String[]) ~ Nil {
    fruit := ["apples", "oranges"];
    fruit->Size()->PrintLine();
  }
}

OCaml

Array.length [|"apple"; "orange"|];;

Oforth

[ "apple", "orange" ] size

Ol

All of these methods are equivalent.

(print (vector-length (vector "apple" "orange")))
(print (vector-length #("apple" "orange")))
(print (vector-length ["apple" "orange"]))

(print (size #("apple" "orange")))

Onyx

[`apple' `orange'] length # leaves 2 on top of the stack

ooRexx

/* REXX */
a = .array~of('apple','orange')
say a~size 'elements'
Do e over a
  say e
  End
Say "a[2]="a[2]

Output:

2 elements
apple
orange
a[2]=orange

PARI/GP

array = ["apple", "orange"]
length(array)       \\ == 2
#array              \\ == 2

The # syntax is a handy shorthand. It usually looks best just on variables but it works on expressions too, possibly with parens to control precedence.

Both forms work on column vectors too, and also on strings and matrices. (For a matrix it is the number of columns.)

Pascal

Works with: Free Pascal version 2.6.2

#!/usr/bin/instantfpc
//program ArrayLength;

{$mode objfpc}{$H+}

uses SysUtils, Classes;

const
  Fruits : array[0..1] of String = ('apple', 'orange');

begin
   WriteLn('Length of Fruits by function : ', Length(Fruits));
   WriteLn('Length of Fruits by bounds : ', High(Fruits) - Low(Fruits) + 1);
END.

Output:

./ArrayLength.pas 
Length of Fruits by function : 2
Length of Fruits by bounds : 2

Perl

The way to get the number of elements of an array in Perl is to put the array in scalar context.

my @array = qw "apple orange banana", 4, 42;

scalar @array;      #  5
0 + @arrray;        #  5
'' . @array;        # "5"
my $elems = @array; # $elems = 5

scalar @{  [1,2,3]  }; # [1,2,3] is a reference which is already a scalar

my $array_ref = \@array; # a reference
scalar @$array_ref;


# using subroutine prototypes, not generally recommended
# and not usually what you think they are
sub takes_a_scalar ($) { my ($a) = @_; return $a }

takes_a_scalar @array;

# the built-ins can also act like they have prototypes

A common mistake is to use length which works on strings not arrays. So using it on an array, as a side-effect, actually gives you a number which represents the order of magnitude.

length '' . @array; # 1
length      @array; # 1

print '0.', scalar @array, 'e', length @array, "\n"; # 0.5e1

@array = 1..123;
print '0.', scalar @array, 'e', length @array, "\n"; # 0.123e3

print 'the length of @array is on the order of ';
print 10 ** (length( @array )-1); # 100
print " elements long\n";

Phix

Library: Phix/basics

constant fruits = {"apple","orange"}
?length(fruits)

Output:

Phixmonti

"apple" "orange" stklen tolist len print

With syntactic sugar

include ..\Utilitys.pmt
( "apple" "orange" ) len print

Output:

PHP

print count(['apple', 'orange']); // Returns 2

Picat

  L = ["apple", "orange"],
  println(len(L))),
  println(length(L)),
  println(L.len),
  println(L.length).</syntaxhighlight>

Output:

PicoLisp

: (length '(apple orange))
-> 2
:

Pike

void main()
{
    array fruit = ({ "apple", "orange" });
    write("%d\n", sizeof(fruit));
}

Output:

PL/I

 p: Proc Options(main);
 Dcl a(2) Char(6) Varying Init('apple','orange');
 Put Edit('Array a has',(hbound(a)-lbound(a)+1),' elements.')
         (Skip,a,f(2),a);
 Put Skip Data(a);
 End;

Output:

Array a has 2 elements.
A(1)='apple'            A(2)='orange';

Plorth

["apple", "orange"] length println

Pony

actor Main
    new create(env:Env)=>
        var c=Array[String](2)
        c.push("apple")
        c.push("orange")
        env.out.print("Array c is " + c.size().string() + " elements long!")

Potion

("apple", "orange") length print

PowerShell

$Array = @( "Apple", "Orange" )
$Array.Count
$Array.Length

Output:

2
2

Processing

String[] arr = {"apple", "orange"};
void setup(){
  println(arr.length);
}

Output:

Processing Python mode

arr = ['apple', 'orange']  # a list for an array

def setup():
    println(len(arr))

Output:

Prolog

| ?- length(["apple", "orange"], X).

X = 2

yes

PureBasic

EnableExplicit
Define Dim fruit$(1); defines array with 2 elements at indices 0 and 1 
fruit$(0) = "apple"
fruit$(1) = "orange"
Define length = ArraySize(fruit$()) + 1; including the element at index 0
If OpenConsole()
  PrintN("The length of the fruit array is " + length)
  PrintN("")
  PrintN("Press any key to close the console")
  Repeat: Delay(10) : Until Inkey() <> ""
  CloseConsole()
EndIf

Output:

The length of the fruit array is 2

An abbreviated form of the above, not printing to console/terminal

Dim fruit$(1); defines array with 2 elements at indices 0 and 1 
fruit$(0) = "apple"
fruit$(1) = "orange"
Debug ArraySize(fruit$()) + 1 ;the number of elements is equal to the size + 1. For example: Dim a(2) contains 3 elements from a(0) to a(2) for a size of 2.

Output:

Python

>>> print(len(['apple', 'orange']))
2
>>>

QB64

Dim max As Integer, Index As Integer
Randomize Timer
max = Int(Rnd * 10) + 1
Dim StringAr(1 To max) As String

For Index = 1 To max
    If Int(Rnd * 6) + 1 <= 3 Then StringAr(Index) = "Apple" Else StringAr(Index) = "orange"
Next
Print UBound(Stringar)
End

Quackery

<Lang Quackery> $ "apples" $ "oranges" 2 pack size echo</syntaxhighlight>

Output:

R

a <- c('apple','orange')   # create a vector containing "apple" and "orange"
length(a)

Output:

[1] 2

Racket

Translation of: EchoLisp

#lang racket/base
(length '("apple" "orange")) ;; list
(vector-length #("apple" "orange")) ;; vector

Output:

2
2

Raku

(formerly Perl 6)

Works with: Rakudo version 2017.04

To get the number of elements of an array in Raku you put the array in a coercing Numeric context, or call elems on it.

my @array = <apple orange>;

say @array.elems;  # 2
say elems @array;  # 2
say + @array;      # 2
say @array + 0;    # 2

Watch out for infinite/lazy arrays though. You can't get the length of those.

my @infinite = 1 .. Inf;  # 1, 2, 3, 4, ...

say @infinite[5000];  # 5001
say @infinite.elems;  # Throws exception "Cannot .elems a lazy list"

Rapira

arr := <* "apple", "orange" *>
output: #arr

Red

length? ["apples" "oranges"]
== 2

Relation

relation fruit
insert "apples"
insert "oranges"
project fruit count
print

fruit_count
2

ReScript

let fruits = ["apple", "orange"]

Js.log(Js.Array.length(fruits))

<!DOCTYPE html>
<html>
<head>
<title>ReScript: Array.length()</title>
<style rel="stylesheet" type="text/css">
body { color:#EEE; background-color:#888; }
</style>
<script>var exports = {};</script>
<script src="./arrlen.js"></script>
</head>
<body>

</body>
</html>

Output:

// Generated by ReScript, PLEASE EDIT WITH CARE
'use strict';

var fruits = [
  "apple",
  "orange"
];

console.log(fruits.length);

exports.fruits = fruits;
/*  Not a pure module */

REXX

/* REXX ----------------------------------------------
* The compond variable a. implements an array
* By convention, a.0 contains the number of elements
*---------------------------------------------------*/
a.=0                   /* initialize the "array" */
call store 'apple'
Call store 'orange'
Say 'There are' a.0 'elements in the array:'
Do i=1 To a.0
  Say 'Element' i':' a.i
  End
Exit
store: Procedure Expose a.
z=a.0+1
a.z=arg(1)
a.0=z
Return

Output:

There are 2 elements in the array:
Element 1: apple
Element 2: orange

Ring

See len(['apple', 'orange']) # output = 2

Robotic

As stated before in the arrays section on this Wiki, there is no functions listed for the manipulation/status of arrays. The best way we can count for length in an array is to have a variable keep track of it.

Example 1:

set "index" to 0
set "$array&index&" to "apple"
inc "index" by 1
set "$array&index&" to "orange"
* "Array length: ('index' + 1)"

Example 2:

set "index" to 0
set "local1" to random 1 to 99
: "rand"
set "array&index&" to random 0 to 99
inc "index" 1
dec "local1" 1
if "local1" > 1 then "rand"
* "Array length: ('index')"

Ruby

puts ['apple', 'orange'].length  # or .size

Rust

By default arrays are immutable in rust.

fn main() {
    let array = ["foo", "bar", "baz", "biff"];
    println!("the array has {} elements", array.len());
}

Scala

println(Array("apple", "orange").length)

Scheme

Using Scheme's vector type as an equivalent to an array:

(display (vector-length #("apple" "orange")))

Seed7

The function length determines the length of an array.

$ include "seed7_05.s7i";

const array string: anArray is [] ("apple", "orange");

const proc: main is func
  begin
    writeln(length(anArray));
  end func;

SenseTalk

put ("apple", "orange", "pear", "banana", "aubergine") into fruits
put the number of items in fruits

Shen

\\ Using a vector
\\ @v creates the vector
\\ <> ends the vector 
\\ limit returns the length of a vector
\\ apple and orange are symbols (vs strings) in this case.
(limit (@v apple orange <>))


\\ As an list
(length [apple orange])

Sidef

var arr = ['apple', 'orange'];
say arr.len;        #=> 2
say arr.end;        #=> 1 (zero based)

Simula

COMMENT ARRAY-LENGTH;
BEGIN

    INTEGER PROCEDURE ARRAYLENGTH(A); TEXT ARRAY A;
    BEGIN
        ARRAYLENGTH := UPPERBOUND(A, 1) - LOWERBOUND(A, 1) + 1;
    END ARRAYLENGTH;

    TEXT ARRAY A(1:2);
    INTEGER L;
    A(1) :- "APPLE";
    A(2) :- "ORANGE";
    L := ARRAYLENGTH(A);
    OUTINT(L, 0);
    OUTIMAGE;
END

Output:

Smalltalk

a := #('apple' 'orange').
a size

SNOBOL4

    ar = ARRAY('2,2')
    ar<1,1> = 'apple'
    ar<1,2> = 'first'
    ar<2,1> = 'orange'
    ar<2,2> = 'second'
    OUTPUT = IDENT(DATATYPE(ar), 'ARRAY') PROTOTYPE(ar)
end

Output:

2,2

SPL

a = ["apple","orange"]
#.output("Number of elements in array: ",#.size(a,1))

Output:

Number of elements in array: 2

SQL

SELECT COUNT() FROM (VALUES ('apple'),('orange'));

Standard ML

let
  val a = Array.fromList ["apple", "orange"]
in
  Array.length a
end;

Stata

String data may be stored either in a Stata dataset or in a Mata matrix, not in a Stata matrix, which may hold only numeric data. A list of strings may also be stored in a Stata macro.

Dimensions of a dataset

clear
input str10 fruit
apple
orange
end

di _N
di c(N) " " c(k)

Length of a macro list

Use either the sizeof macro list function or the word count extended macro function. Notice that the argument of the former is the macro name, while the argument of the latter is the macro contents.

local fruits apple orange
di `: list sizeof fruits'
di `: word count `fruits''

Mata

For a Mata array, use rows and similar functions:

mata
a=st_sdata(.,"fruit")
rows(a)
cols(a)
length(a)
end

Swift

let fruits = ["apple", "orange"] // Declare constant array literal
let fruitsCount = fruits.count // Declare constant array length (count)

print(fruitsCount) // Print array length to output window

Output:

Symsyn

| Symsyn does not support Array of Strings
| The following code for an Array of Integers

A : 125 0
  #A []
| shows 125

| A list of fixed length strings can be handled this way

S : 'apple ' : 'orange'
  div #S 6 sz
  sz []
| shows 2

Tailspin

['apple', 'orange'] -> $::length -> !OUT::write

Output:

Tcl

;# not recommended:
set mylistA {apple orange}   ;# actually a string
set mylistA "Apple Orange"   ;# same - this works only for simple cases

set lenA [llength $mylistA]
puts "$mylistA :  $lenA"

# better:  to build a list, use 'list' and/or 'lappend':
set mylistB [list apple orange "red wine" {green frog}]
lappend mylistB "blue bird"

set lenB [llength $mylistB]
puts "$mylistB :  $lenB"

Output:

Apple Orange :  2
apple orange {red wine} {green frog} {blue bird} :  5

TI-83 BASIC

Works with: TI-83 2.55MP

Use function dim().

{1,3,–5,4,–2,–1}→L1
dim(L1)

Output:

Transd

#lang transd

MainModule : {
    _start: (lambda 
        (with v ["apple", "orange"]
            (lout (size v))
        )
        (lout (size ["apple", "orange"]))
    )
}

Output:

2
2

UNIX Shell

#!/bin/bash
array=("orange" "apple")
echo "${#array[@]}"

Output:

Ursa

> decl string<> stream
> append "two" "strings" stream
> out (size stream) endl console
2
> out (size "test string") endl console
11
>

Vala

void main() {
  string[] fruit = {"apple", "orange"};
  stdout.printf("%d\n", fruit.length);
}

Note that any of the following array declarations could be used:

var fruit = new string[] { "apple", "orange" };
string[] fruit = new string[] { "apple", "orange" };
string[] fruit = { "apple", "orange" };

A shorter variant could also have been used:

void main() {
  stdout.printf("%d\n", new string[] {"apples", "orange"}.length);
}

VBA

One-liner. Assumes array lower bound, which is not always safe.

Debug.Print "Array Length: " & UBound(Array("apple", "orange")) + 1

Works regardless of lower bound:

Dim funkyArray(7 to 8) As String

Public Function SizeOfArray(ar As Variant) As Long
  SizeOfArray = UBound(ar) - LBound(ar) + 1
End Function

'call the function
Debug.Print "Array Length: " & SizeOfArray(funkyArray)

Output:

In this instance, same output for both.

Array Length: 2

VBScript

arr = Array("apple","orange")
WScript.StdOut.WriteLine UBound(arr) - LBound(arr) + 1

Output:

Visual Basic

The amount of elements in an array in Visual Basic is computed via the upper bound and lower bound indices. In Visual Basic the indices of arrays have to be numeric, but it is even possible to have negative values for them. Of course the element numbering is continuous.

' declared in a module
Public Function LengthOfArray(ByRef arr As Variant) As Long
  If IsArray(arr) Then
     LengthOfArray = UBound(arr) - LBound(arr) + 1
  Else
     LengthOfArray = -1
  End If
End Function

' somewhere in the programm
' example 1
  Dim arr As Variant
  
  arr = Array("apple", "orange")
  
  Debug.Print LengthOfArray(arr) ' prints 2 as result

' example 2
  Dim arr As Variant
  
  ReDim arr(-2 To -1)
  arr(-2) = "apple"
  arr(-1) = "orange"

  Debug.Print LengthOfArray(arr) ' prints 2 as result

Visual Basic .NET

Works with: Visual Basic .NET version 9.0+

Module ArrayLength

    Sub Main()
        Dim array() As String = {"apple", "orange"}
        Console.WriteLine(array.Length)
    End Sub

End Module

Output:

Vlang

A len property is maintained for all V arrays.

// V, array length
// Tectonics: v run array-length.v
module main

// access array length
pub fn main() {
    arr := ["apple", "orange"]
    println(arr.len)
}

Output:

prompt$ v run array-length.v
2

WDTE

let io => import 'io';
let a => ['apple'; 'orange'];
len a -- io.writeln io.stdout;

Wren

var arr = ["apple", "orange"]
System.print(arr.count)

Output:

XLISP

(vector-length #("apple" "orange"))

Yabasic

dim fruta$(3)
read fruta$(1), fruta$(2), fruta$(3)
data "apple", "orange", "pear"

print arraysize(fruta$(),1)
print fruta$(2)
end

3
orange

Z80 Assembly

Arrays don't have an "end" as defined by the language, so there are a couple ways to mark the end of an array. One is with a null terminator, and the other is with a pre-defined size byte stored at the beginning. Using a null terminator isn't the best choice for a general-purpose array since it means your array cannot contain that value anywhere except at the end. However, since having the size already determined defeats the purpose of this task, the null-terminator method will be used for this example.

The simplest way to implement an array of variable-length strings is to have the array contain pointers to said strings rather than the strings themselves. That way, the elements of the array are of equal length, which makes any array much easier to work with.

	org &8000
	ld hl,TestArray
	call GetArrayLength_WordData_NullTerminated
	
	call Monitor            ;show registers to screen, code omitted to keep this example short
	
ReturnToBasic:
	RET
	
GetArrayLength_WordData_NullTerminated:
	push hl			;we'll need this later
loop_GetArrayLength_WordData_NullTerminated
	ld a,(hl)		;get the low byte
	ld e,a			;stash it in E
	inc hl			;next byte
	ld a,(hl)		;get the high byte
	dec hl			;go back to low byte, otherwise our length will be off.
	or a			;compare to zero. This is a shorter and faster way to compare A to zero than "CP 0"
	
	jr nz,keepGoing
		cp e		;compare to E
		jr z,Terminated_GetArrayLength			        ;both bytes were zero.
KeepGoing:
	inc hl											
	inc hl								;next word
	jp loop_GetArrayLength_WordData_NullTerminated	                ;back to start
Terminated_GetArrayLength:
	pop de		;original array address is in DE
	;or a		;normally it's best to clear the carry, but in this situation execution only arrives here after a compare that
                        ;resulted in an equality to zero, which means the carry is guaranteed to be cleared.
	sbc hl,de	;there is no sub hl,de; only sbc
	
	srl h
	rr l		;divide HL by 2, since each element is 2 bytes.
	
	ret		;returns length in hl

TestArray:
	word Apple,Orange
	byte 0,0
	
Apple:
	byte "Apple",0
Orange:
	byte "Orange",0

Output:

(HL contains length of the array)
HL:0002

zkl

zkl doesn't support arrays natively, use lists instead.

List("apple", "orange").len().println() //-->2, == L("apple", "orange")
T("apple", "orange").len().println() //-->2, read only list (ROList)

Zig

const std = @import("std");

pub fn main() !void {
    // left hand side type can be ommitted
    const fruit: [2][]const u8 = [_][]const u8{ "apples", "oranges" };
    const stdout_wr = std.io.getStdOut().writer();
    // slices and arrays have an len field
    try stdout_wr.print("fruit.len = {d}\n", .{fruit.len});
}

Zoea

program: array_length
  input: [a,b,c]
  output: 3

Zoea Visual

Array Length

zonnon

module AryLength;
type
	Vector = array 12 of string;
	Matrix = array *,* of string;
var
	a: Vector;
	b: Matrix;
begin
	writeln(len(a):4);		(* len(a) = len(a,0) *)

	b := new Matrix(10,11);
	writeln(len(b,0):4); 	(* first dimension *)
	writeln(len(b,1):4)		(* second dimension *)
end AryLength.