# Order two numerical lists

Order two numerical lists
You are encouraged to solve this task according to the task description, using any language you may know.

Tasks in this category have to do with sorting collections of objects.

Sorting Algorithm
This is a sorting algorithm.   It may be applied to a set of data in order to sort it.     For comparing various sorts, see compare sorts.   For other sorting algorithms,   see sorting algorithms,   or:

O(n logn) sorts

O(n log2n) sorts
Shell Sort

Write a function that orders two lists or arrays filled with numbers. The function should accept two lists as arguments and return true if the first list should be ordered before the second, and false otherwise.

The order is determined by lexicographic order: Comparing the first element of each list. If the first elements are equal, then the second elements should be compared, and so on, until one of the list has no more elements. If the first list runs out of elements the result is true. If the second list or both run out of elements the result is false.

Note: further clarification of lexicographical ordering is expounded on the talk page here and here.

## 11l

Translation of: Python
[1,2,1,3,2] < [1,2,0,4,4,0,0,0]

## AArch64 Assembly

Works with: as version Raspberry Pi 3B version Buster 64 bits
/* ARM assembly AARCH64 Raspberry PI 3B */
/*  program orderlist64.s   */

/*******************************************/
/* Constantes file                         */
/*******************************************/
/* for this file see task include a file in language AArch64 assembly*/
.include "../includeConstantesARM64.inc"

/*********************************/
/* Initialized data              */
/*********************************/
.data
szMessResult1:      .asciz "List1 < List2 \n"           // message result
szMessResult2:      .asciz "List1 => List2 \n"           // message result
szCarriageReturn:  .asciz "\n"

.equ NBELEMENTS1,   (. - qTabList1) /8
.equ NBELEMENTS2,   (. - qTabList2) /8
.equ NBELEMENTS3,   (. - qTabList3) /8
.equ NBELEMENTS4,   (. - qTabList4) /8
/*********************************/
/* UnInitialized data            */
/*********************************/
.bss
/*********************************/
/*  code section                 */
/*********************************/
.text
.global main
main:                                       // entry of program
mov x1,NBELEMENTS1
mov x3,NBELEMENTS2
bl listeOrder
cmp x0,0                                // false ?
beq 1f                                  // yes
ldr x0,qAdrszMessResult1                // list 1 < list 2
bl affichageMess                        // display message
b 2f
1:
bl affichageMess                        // display message

2:
mov x1,NBELEMENTS1
mov x3,NBELEMENTS3
bl listeOrder
cmp x0,0                               // false ?
beq 3f                                  // yes
ldr x0,qAdrszMessResult1                // list 1 < list 2
bl affichageMess                        // display message
b 4f
3:
bl affichageMess                        // display message
4:
mov x1,NBELEMENTS1
mov x3,NBELEMENTS4
bl listeOrder
cmp x0,0                               // false ?
beq 5f                                  // yes
ldr x0,qAdrszMessResult1                // list 1 < list 2
bl affichageMess                        // display message
b 6f
5:
bl affichageMess                        // display message
6:
100:                                        // standard end of the program
mov x0,0                              // return code
mov x8,EXIT                           // request to exit program
svc 0                                  // perform the system call
/******************************************************************/
/*     liste order                                                */
/******************************************************************/
/* x0 contains the address of list 1 */
/* x1 contains list 1 size           */
/* x2 contains the address of list 2 */
/* x3 contains list 2 size           */
/* x0 returns 1 if list1 < list2     */
/* x0 returns 0 else                 */
listeOrder:
stp x1,lr,[sp,-16]!          // save  registers
stp x2,x3,[sp,-16]!          // save  registers
cbz x1,99f                    // list 1 size = zero ?
cbz x3,98f                    // list 2 size = zero ?

mov x4,#0                    // index list 1
mov x5,#0                    // index list 2
1:
ldr x6,[x0,x4,lsl #3]        // load list 1 element
ldr x8,[x2,x5,lsl #3]        // load list 2 element
cmp x6,x8                    // compar
bgt 4f
beq 2f                       // list 1 = list 2
add x4,x4,1                  // increment index 1
cmp x4,x1                    // end list ?
bge 5f
b 1b                         // else loop
2:
add x4,x4,1                  // increment index 1
cmp x4,x1                    // end list ?
bge 3f                       // yes -> verif size
add x5,x5,1                  // else increment index 2
cmp x5,x3                    // end list 2 ?
bge 4f
b 1b                         // else loop
3:
cmp x1,x3                     // compar size
bge 4f                       // list 2 < list 1
blt 5f                       // list 1 < list 2
b 100f
4:
mov x0,#0                    // list 1 > list 2
b 100f
5:
mov x0,#1                    //  list 1 < list 2
b 100f
98:                              // error
mov x0,-2
b 100f
99:                              // error
mov x0,-1
100:
ldp x2,x3,[sp],16            // restaur  2 registers
ldp x1,lr,[sp],16            // restaur  2 registers
/********************************************************/
/*        File Include fonctions                        */
/********************************************************/
/* for this file see task include a file in language AArch64 assembly */
.include "../includeARM64.inc"

## ACL2

The built-in lexorder does this.

ACL2 !>(lexorder '(1 2 3) '(1 2 3 4))
T
ACL2 !>(lexorder '(1 2 4) '(1 2 3))
NIL

## Action!

INT FUNC Compare(INT ARRAY x INT xLen INT ARRAY y INT yLen)
INT i,len

len=xLen
IF len>yLen THEN
len=yLen
FI
FOR i=0 TO len-1
DO
IF x(i)>y(i) THEN
RETURN (1)
ELSEIF x(i)<y(i) THEN
RETURN (-1)
FI
OD
IF xLen>yLen THEN
RETURN (1)
ELSEIF xLen<yLen THEN
RETURN (-1)
FI
RETURN (0)

BYTE FUNC Less(INT ARRAY x INT xLen INT ARRAY y INT yLen)
IF Compare(x,xLen,y,yLen)<0 THEN
RETURN (1)
FI
RETURN (0)

PROC PrintArray(INT ARRAY x INT len)
INT i

Put('[)
FOR i=0 TO len-1
DO
PrintI(x(i))
IF i<len-1 THEN
Put(' )
FI
OD
Put('])
RETURN

PROC Test(INT ARRAY x INT xLen INT ARRAY y INT yLen)
PrintArray(x,xLen)
IF Less(x,xLen,y,yLen) THEN
Print(" < ")
ELSE
Print(" >= ")
FI
PrintArray(y,yLen) PutE()
RETURN

PROC Main()
INT ARRAY a=[1 2 1 5 2]
INT ARRAY b=[1 2 1 5 2 2]
INT ARRAY c=[1 2 3 4 5]
INT ARRAY d=[1 2 3 4 5]

Test(a,5,b,6)
Test(b,6,a,5)
Test(b,6,c,5)
Test(c,5,b,6)
Test(c,5,d,5)
RETURN
Output:
[1 2 1 5 2] < [1 2 1 5 2 2]
[1 2 1 5 2 2] >= [1 2 1 5 2]
[1 2 1 5 2 2] < [1 2 3 4 5]
[1 2 3 4 5] >= [1 2 1 5 2 2]
[1 2 3 4 5] >= [1 2 3 4 5]

This is already implemented in the built-in comparison operators for arrays of types that have a direct ordering. This also includes arrays of user defined types, using the type definition order from smallest to largest. Demonstrated in the program below:

procedure Order is

type IntArray is array (Positive range <>) of Integer;
List1 : IntArray := (1, 2, 3, 4, 5);
List2 : IntArray := (1, 2, 1, 5, 2, 2);
List3 : IntArray := (1, 2, 1, 5, 2);
List4 : IntArray := (1, 2, 1, 5, 2);

type Animal is (Rat, Cat, Elephant);
type AnimalArray is array (Positive range <>) of Animal;
List5 : AnimalArray := (Cat, Elephant, Rat, Cat);
List6 : AnimalArray := (Cat, Elephant, Rat);
List7 : AnimalArray := (Cat, Cat, Elephant);

begin
Put_Line (Boolean'Image (List1 > List2)); --  True
Put_Line (Boolean'Image (List2 > List3)); --  True
Put_Line (Boolean'Image (List3 > List4)); --  False, equal
Put_Line (Boolean'Image (List5 > List6)); --  True
Put_Line (Boolean'Image (List6 > List7)); --  True
end Order;
Output:
TRUE
TRUE
FALSE
TRUE
TRUE

## ALGOL 68

BEGIN # compare lists (rows) of integers #
# returns TRUE if there is an element in a that is < the corresponding #
# element in b and all previous elements are equal; FALSE otherwise    #
OP < = ( []INT a, b )BOOL:
IF  INT  a pos  := LWB a;
INT  b pos  := LWB b;
BOOL equal  := TRUE;
WHILE a pos <= UPB a AND b pos <= UPB b AND equal DO
equal := a[ a pos ] = b[ b pos ];
IF equal THEN
a pos +:= 1;
b pos +:= 1
FI
OD;
NOT equal
THEN
# there is an element in a and b that is not equal #
a[ a pos ] < b[ b pos ]
ELSE
# all elements are equal or one list is shorter #
# a is < b if a has fewer elements #
a pos > UPB a AND b pos <= UPB b
FI # < # ;

# tests a < b has the expected result #
PROC test = ( STRING a name, []INT a, STRING b name, []INT b, BOOL expected )VOID:
BEGIN
BOOL result = a < b;
print( ( a name, IF result THEN " <  " ELSE " >= " FI, b name
, IF result = expected THEN "" ELSE ", NOT as expected" FI
, newline
)
)
END # test # ;

# test cases as in the BBC basic sample #
[]INT list1 = ( 1, 2, 1, 5, 2 );
[]INT list2 = ( 1, 2, 1, 5, 2, 2 );
[]INT list3 = ( 1, 2, 3, 4, 5 );
[]INT list4 = ( 1, 2, 3, 4, 5 );
test( "list1", list1, "list2", list2, TRUE  );
test( "list2", list2, "list3", list3, TRUE  );
test( "list3", list3, "list4", list4, FALSE );

[]INT list5 = ( 9, 0, 2, 1, 0 );
[]INT list6 = ( 4, 0, 7, 7 );
[]INT list7 = ( 4, 0, 7    );
[]INT list8 = ( );
test( "list5", list5, "list6", list6, FALSE );
test( "list6", list6, "list7", list7, FALSE );
test( "list7", list7, "list8", list8, FALSE );
test( "list8", list8, "list7", list7, TRUE  )

END
Output:
list1 <  list2
list2 <  list3
list3 >= list4
list5 >= list6
list6 >= list7
list7 >= list8
list8 <  list7

## ALGOL W

Translation of: ALGOL 68
begin % compare lists (rows) of integers %
% returns TRUE if there is an element in a that is < the corresponding %
% element in b and all previous elements are equal, FALSE otherwise    %
% the bounds of a and b should aLb :: aUb and bLb :: bUb               %
logical procedure iLT ( integer array a ( * )
; integer value aLb, aUb
; integer array b ( * )
; integer value bLb, bUb
) ;
begin
integer aPos, bPos;
logical equal;
aPos := aLb;
bPos := bLb;
equal := true;
while aPos <= aUb and bPos <= bUb and equal do begin
equal := a( aPos ) = b( bPos );
if equal then begin
aPos := aPOs + 1;
bPos := bPos + 1
end if_equal
end while_more_elements_and_equal ;
if not equal
then % there is an element in a and b that is not equal %
a( aPos ) < b( bPos )
else % all elements are equal or one list is shorter %
% a is < b if a has fewer elements %
aPos > aUb and bPos <= bUb
end iLT ;
% tests a < b has the expected result %
procedure test ( string(5) value aName
; integer array a ( * )
; integer value aLb, aUb
; string(5) value bName
; integer array b ( * )
; integer value bLb, bUb
; logical value expected
) ;
begin
logical isLt;
isLt := iLT( a, aLb, aUb, b, bLb, bUb );
write( aName, if isLt then " <  " else " >= ", bName
, if isLt = expected then "" else ", NOT as expected"
)
end test ;

integer array list1, list3, list4 ( 1 :: 5 );
integer array list2               ( 1 :: 6 );
integer array list5               ( 1 :: 5 );
integer array list6               ( 1 :: 4 );
integer array list7               ( 1 :: 3 );
integer array list8               ( 1 :: 1 );
integer aPos;
% test cases as in the BBC basic sample %
aPos := 1; for i := 1, 2, 1, 5, 2    do begin list1( aPos ) := i; aPos := aPos + 1 end;
aPos := 1; for i := 1, 2, 1, 5, 2, 2 do begin list2( aPos ) := i; aPos := aPos + 1 end;
aPos := 1; for i := 1, 2, 3, 4, 5    do begin list3( aPos ) := i; aPos := aPos + 1 end;
aPos := 1; for i := 1, 2, 3, 4, 5    do begin list4( aPos ) := i; aPos := aPos + 1 end;
test( "list1", list1, 1, 5, "list2", list2, 1, 6, true  );
test( "list2", list2, 1, 6, "list3", list3, 1, 5, true  );
test( "list3", list3, 1, 5, "list4", list4, 1, 5, false );
aPos := 1; for i := 9, 0, 2, 1, 0    do begin list5( aPos ) := i; aPos := aPos + 1 end;
aPos := 1; for i := 4, 0, 7, 7       do begin list6( aPos ) := i; aPos := aPos + 1 end;
aPos := 1; for i := 4, 0, 7          do begin list7( aPos ) := i; aPos := aPos + 1 end;
test( "list5", list5, 1, 5, "list6", list6, 1, 4, false );
test( "list6", list6, 1, 4, "list7", list7, 1, 3, false );
test( "list7", list7, 1, 3, "list8", list8, 1, 0, false );
test( "list8", list8, 1, 0, "list7", list7, 1, 3, true  )
end.
Output:
list1 <  list2
list2 <  list3
list3 >= list4
list5 >= list6
list6 >= list7
list7 >= list8
list8 <  list7

## Aime

ordl(list a, b)
{
integer i, l, o;

l = min(~a, ~b);
i = 0;
while (i < l) {
if (a[i] != b[i]) {
o = a[i] < b[i];
break;
}

i += 1;
}

i < l ? o : ~a <= ~b;
}

main(void)
{
o_(ordl(list(1, 2), list(1, 2)), "\n");
o_(ordl(list(1e2, 2), list(1e2, 2, 3)), "\n");
o_(ordl(list(1, 2, 3), list(1, 2)), "\n");
o_(ordl(list(.5, 4), list(.5, 2)), "\n");
o_(ordl(list(1, 4, 2, 3), list(1, 4, 2.1, 3)), "\n");

0;
}

## AppleScript

Translation of: JavaScript

<= is not defined over lists in AppleScript

-- <= for lists
-- compare :: [a] -> [a] -> Bool
on compare(xs, ys)
if length of xs = 0 then
true
else
if length of ys = 0 then
false
else
set {hx, txs} to uncons(xs)
set {hy, tys} to uncons(ys)

if hx = hy then
compare(txs, tys)
else
hx < hy
end if
end if
end if
end compare

-- TEST
on run

{compare([1, 2, 1, 3, 2], [1, 2, 0, 4, 4, 0, 0, 0]), ¬
compare([1, 2, 0, 4, 4, 0, 0, 0], [1, 2, 1, 3, 2])}

end run

---------------------------------------------------------------------------

-- GENERIC FUNCTION

-- uncons :: [a] -> Maybe (a, [a])
on uncons(xs)
if length of xs > 0 then
{item 1 of xs, rest of xs}
else
missing value
end if
end uncons
Output:
{false, true}

Here's an iterative implementation:

on listAComesBeforeListB(a, b)
set aLength to (count a)
set bLength to (count b)
set i to 0
repeat
set i to i + 1
if (i > bLength) then
return false
else if (i > aLength) then
return true
else
set aVal to item i of a
set bVal to item i of b
if (aVal = bVal) then
else
return (bVal > aVal)
end if
end if
end repeat
end listAComesBeforeListB

-- Test code:
set a to {}
repeat (random number 10) times
set end of a to random number 10
end repeat
set b to {}
repeat (random number 10) times
set end of b to random number 10
end repeat

return {a:a, b:b, | a < b |: listAComesBeforeListB(a, b)},
Output:

Examples:

{a:{3, 5, 6, 5, 2, 1, 4}, b:{5, 8, 9, 2, 0, 1, 9, 0, 4, 10}, | a < b |:true}
{a:{10, 9, 5, 8, 8, 4, 3}, b:{5, 10, 8, 9, 10, 8, 7, 8}, | a < b |:false}
{a:{0, 10}, b:{0, 10}, | a < b |:false}
{a:{0, 10}, b:{0, 10, 5}, | a < b |:true}

## ARM Assembly

Works with: as version Raspberry Pi
/* ARM assembly Raspberry PI  */
/*  program orderlist.s   */

/* Constantes    */
.equ STDOUT, 1     @ Linux output console
.equ EXIT,   1     @ Linux syscall
.equ WRITE,  4     @ Linux syscall

/*********************************/
/* Initialized data              */
/*********************************/
.data
szMessResult1:      .asciz "List1 < List2 \n"           @ message result
szMessResult2:      .asciz "List1 => List2 \n"           @ message result
szCarriageReturn:  .asciz "\n"

iTabList1:         .int  1,2,3,4,5
.equ NBELEMENTS1,   (. - iTabList1) /4
iTabList2:         .int  1,2,1,5,2,2
.equ NBELEMENTS2,   (. - iTabList2) /4
iTabList3:         .int  1,2,3,4,5
.equ NBELEMENTS3,   (. - iTabList3) /4
iTabList4:         .int  1,2,3,4,5,6
.equ NBELEMENTS4,   (. - iTabList4) /4
/*********************************/
/* UnInitialized data            */
/*********************************/
.bss
/*********************************/
/*  code section                 */
/*********************************/
.text
.global main
main:                                       @ entry of program
mov r1,#NBELEMENTS1
mov r3,#NBELEMENTS2
bl listeOrder
cmp r0,#0                               @ false ?
beq 1f                                  @ yes
ldr r0,iAdrszMessResult1                @ list 1 < list 2
bl affichageMess                        @ display message
b 2f
1:
bl affichageMess                        @ display message

2:
mov r1,#NBELEMENTS1
mov r3,#NBELEMENTS3
bl listeOrder
cmp r0,#0                               @ false ?
beq 3f                                  @ yes
ldr r0,iAdrszMessResult1                @ list 1 < list 2
bl affichageMess                        @ display message
b 4f
3:
bl affichageMess                        @ display message
4:
mov r1,#NBELEMENTS1
mov r3,#NBELEMENTS4
bl listeOrder
cmp r0,#0                               @ false ?
beq 5f                                  @ yes
ldr r0,iAdrszMessResult1                @ list 1 < list 2
bl affichageMess                        @ display message
b 6f
5:
bl affichageMess                        @ display message
6:
100:                                        @ standard end of the program
mov r0, #0                              @ return code
mov r7, #EXIT                           @ request to exit program
svc #0                                  @ perform the system call
/******************************************************************/
/*     display text with size calculation                         */
/******************************************************************/
/* r0 contains the address of list 1 */
/* r1 contains list 1 size           */
/* r2 contains the address of list 2 */
/* r3 contains list 2 size           */
/* r0 returns 1 if list1 < list2     */
/* r0 returns 0 else                 */
listeOrder:
push {r1-r7,lr}                   @ save  registres
cmp r1,#0                         @ list 1 size = zero ?
moveq r0,#-1                      @ yes -> error
beq 100f
cmp r3,#0                         @ list 2 size = zero ?
moveq r0,#-2                      @ yes -> error
beq 100f
mov r4,#0                         @ index list 1
mov r5,#0                         @ index list 2
1:
ldr r6,[r0,r4,lsl #2]             @ load list 1 element
ldr r7,[r2,r5,lsl #2]             @ load list 2 element
cmp r6,r7                         @ compar
movgt r0,#0                       @ list 1 > list 2 ?
bgt 100f
beq 2f                            @ list 1 = list 2
add r4,#1                         @ increment index 1
cmp r4,r1                         @ end list ?
movge r0,#1                       @ yes -> ok list 1 < list 2
bge 100f
b 1b                              @ else loop
2:
add r4,#1                         @ increment index 1
cmp r4,r1                         @ end list ?
bge 3f                            @ yes -> verif size
add r5,#1                         @ else increment index 2
cmp r5,r3                         @ end list 2 ?
movge r0,#0                       @ yes -> list 2 < list 1
bge 100f
b 1b                              @ else loop
3:
cmp r1,r3                          @ compar size
movge r0,#0                        @ list 2 < list 1
movlt r0,#1                        @ list 1 < list 2
100:
pop {r1-r7,lr}                    @ restaur registers
bx lr                             @ return
/******************************************************************/
/*     display text with size calculation                         */
/******************************************************************/
/* r0 contains the address of the message */
affichageMess:
push {r0,r1,r2,r7,lr}                   @ save  registres
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
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"
svc #0                                  @ call systeme
pop {r0,r1,r2,r7,lr}                    @ restaur registers */
bx lr                                   @ return

## Arturo

compareLists: function [a,b][
loop 0..min @[size a, size b] 'i [
if a\[i] < b\[i] -> return true
if a\[i] > b\[i] -> return false
]
return less? size a size b
]

alias.infix '<=> 'compareLists

do [
print [1 2 1 3 2] <=> [1 2 0 4 4 0 0 0]
]
Output:
false

## AutoHotkey

Works with: AutoHotkey_L

The function is overkill as we can just compare the list's ObjMaxIndex()

List1 := [1,2,1,3,2]
List2 := [1,2,0,4,4,0,0,0]
MsgBox % order(List1, List2)

order(L1, L2){
return L1.MaxIndex() < L2.MaxIndex()
}

## AWK

# syntax: GAWK -f ORDER_TWO_NUMERICAL_LISTS.AWK
BEGIN {
split("1,2,1,5,2",list1,",")
split("1,2,1,5,2,2",list2,",")
split("1,2,3,4,5",list3,",")
split("1,2,3,4,5",list4,",")
x = compare_array(list1,list2) ? "<" : ">=" ; printf("list1%slist2\n",x)
x = compare_array(list2,list3) ? "<" : ">=" ; printf("list2%slist3\n",x)
x = compare_array(list3,list4) ? "<" : ">=" ; printf("list3%slist4\n",x)
exit(0)
}
function compare_array(arr1,arr2,  ans,i) {
ans = 0
for (i=1; i<=length(arr1); i++) {
if (arr1[i] != arr2[i]) {
ans = 1
break
}
}
if (length(arr1) != length(arr2)) {
ans = 1
}
return(ans)
}
Output:
list1<list2
list2<list3
list3>=list4

## BASIC256

Translation of: FreeBASIC
arraybase 1
dim list1(5): dim list2(6): dim list3(5): dim list4(5)
list1 = {1, 2, 1, 5, 2}
list2 = {1, 2, 1, 5, 2, 2}
list3 = {1, 2, 3, 4, 5}
list4 = {1, 2, 3, 4, 5}

if Orden(list1[], list2[]) then print "list1 < list2" else print "list 1>= list2"
if Orden(list2[], list3[]) then print "list2 < list3" else print "list2 >= list3"
if Orden(list3[], list4[]) then print "list3 < list4" else print "list3 >= list4"
end

function Orden(listA[], listB[])
i = 0
l1 = listA[?]
l2 = listB[?]
while (listA[i] = listB[i]) and i < l1 and i < l2
i = i + 1
end	while
if listA[?] < listB[?] then return True
if listA[?] > listB[?] then return False
return l1 < l2
end function
Output:
Igual que la entrada de BBC BASIC.

## BBC BASIC

'Ordered before' means 'less than' (see talk page).

DIM list1(4) : list1() = 1, 2, 1, 5, 2
DIM list2(5) : list2() = 1, 2, 1, 5, 2, 2
DIM list3(4) : list3() = 1, 2, 3, 4, 5
DIM list4(4) : list4() = 1, 2, 3, 4, 5

IF FNorder(list1(), list2()) PRINT "list1<list2" ELSE PRINT "list1>=list2"
IF FNorder(list2(), list3()) PRINT "list2<list3" ELSE PRINT "list2>=list3"
IF FNorder(list3(), list4()) PRINT "list3<list4" ELSE PRINT "list3>=list4"
END

DEF FNorder(list1(), list2())
LOCAL i%, l1%, l2%
l1% = DIM(list1(),1) : l2% = DIM(list2(),1)
WHILE list1(i%) = list2(i%) AND i% < l1% AND i% < l2%
i% += 1
ENDWHILE
IF list1(i%) < list2(i%) THEN = TRUE
IF list1(i%) > list2(i%) THEN = FALSE
= l1% < l2%
Output:
list1<list2
list2<list3
list3>=list4

## Bracmat

When evaluating a sum or a product, Bracmat creates an expression with a canonical order, which happens to be compatible with the order defined in this task. In a pattern, only a sum or product on the left hand side (lhs) of the match (:) operator is evaluated. In the solution below we match a composition of the two function arguments into a sum of two terms with itself. If the match expression succeeds, the lhs must already have been in canonical order before evaluation, which means that the first argument is smaller than the second argument. In that case the function outputs FALSE. Notice that if the arguments are the same, evaluation of the sum produces the product of one of the terms and a factor two. This complicates the pattern a bit.

(  1 2 3 4 5:?List1
& 1 2 1 5 2 2:?List2
& 1 2 1 5 2:?List3
& 1 2 1 5 2:?List4
& Cat Elephant Rat Cat:?List5
& Cat Elephant Rat:?List6
& Cat Cat Elephant:?List7
& ( gt
=   first second
.   !arg:(?first,?second)
&   out
\$ (     (.!first)+(.!second)
: ((.!first)+(.!second)|2*(.!first))
& FALSE
| TRUE
)
)
& gt\$(!List1,!List2)
& gt\$(!List2,!List3)
& gt\$(!List3,!List4)
& gt\$(!List4,!List5)
& gt\$(!List5,!List6)
& gt\$(!List6,!List7)
);
Output:
TRUE
TRUE
FALSE
FALSE
TRUE
TRUE

## C

int list_cmp(int *a, int la, int *b, int lb)
{
int i, l = la;
if (l > lb) l = lb;
for (i = 0; i < l; i++) {
if (a[i] == b[i]) continue;
return (a[i] > b[i]) ? 1 : -1;
}
if (la == lb) return 0;
return la > lb ? 1 : -1;
}

This funciton returns one of three states, not a boolean. One can define boolean comparisons, such as list_less_or_eq, based on it:

#define list_less_or_eq(a,b,c,d) (list_cmp(a,b,c,d) != 1)

## C#

namespace RosettaCode.OrderTwoNumericalLists
{
using System;
using System.Collections.Generic;

internal static class Program
{
private static bool IsLessThan(this IEnumerable<int> enumerable,
IEnumerable<int> otherEnumerable)
{
using (
IEnumerator<int> enumerator = enumerable.GetEnumerator(),
otherEnumerator = otherEnumerable.GetEnumerator())
{
while (true)
{
if (!otherEnumerator.MoveNext())
{
return false;
}

if (!enumerator.MoveNext())
{
return true;
}

if (enumerator.Current == otherEnumerator.Current)
{
continue;
}

return enumerator.Current < otherEnumerator.Current;
}
}
}

private static void Main()
{
Console.WriteLine(
new[] {1, 2, 1, 3, 2}.IsLessThan(new[] {1, 2, 0, 4, 4, 0, 0, 0}));
}
}
}
Output:
False

## C++

The built-in comparison operators already do this:

#include <iostream>
#include <vector>

int main() {
std::vector<int> a;
a.push_back(1);
a.push_back(2);
a.push_back(1);
a.push_back(3);
a.push_back(2);
std::vector<int> b;
b.push_back(1);
b.push_back(2);
b.push_back(0);
b.push_back(4);
b.push_back(4);
b.push_back(0);
b.push_back(0);
b.push_back(0);

std::cout << std::boolalpha << (a < b) << std::endl; // prints "false"
return 0;
}

(defn lex? [a b]
(compare a b))

## Common Lisp

(defun list< (a b)
(cond ((not b) nil)
((not a) t)
((= (first a) (first b))
(list< (rest a) (rest b)))
(t (< (first a) (first b)))))

Alternate version

(defun list< (a b)
(let ((x (find-if-not #'zerop (mapcar #'- a b))))
(if x (minusp x) (< (length a) (length b)))))

## D

The built-in comparison operators already do this:

void main() {
assert([1,2,1,3,2] >= [1,2,0,4,4,0,0,0]);
}

## Delphi

Translation of: Java

This is not a full translate of Java, just adaptation and aplication of method previus introduced.

program Order_two_numerical_lists;

{\$APPTYPE CONSOLE}

uses
System.SysUtils,
System.Generics.Defaults;

type
TArray = record
class function LessOrEqual<T>(first, second: TArray<T>): Boolean; static;
end;

class function TArray.LessOrEqual<T>(first, second: TArray<T>): Boolean;
begin
if Length(first) = 0 then
exit(true);
if Length(second) = 0 then
exit(false);
var comp := TComparer<T>.Default.Compare(first[0], second[0]);
if comp = 0 then
exit(LessOrEqual(copy(first, 1, length(first)), copy(second, 1, length(second))));
Result := comp < 0;
end;

begin
writeln(TArray.LessOrEqual<Integer>([1, 2, 3], [2, 3, 4]));
writeln(TArray.LessOrEqual<Integer>([2, 3, 4], [1, 2, 3]));
writeln(TArray.LessOrEqual<Integer>([1, 2], [1, 2, 3]));
writeln(TArray.LessOrEqual<Integer>([1, 2, 3], [1, 2]));
writeln(TArray.LessOrEqual<Char>(['a', 'c', 'b'], ['a', 'b', 'b']));
writeln(TArray.LessOrEqual<string>(['this', 'is', 'a', 'test'], ['this', 'is',
'not', 'a', 'test']));
end.
Output:
TRUE
FALSE
TRUE
FALSE
FALSE
TRUE

## EasyLang

Translation of: C
func listcmp a[] b[] .
for i to lower len a[] len b[]
if a[i] < b[i]
return -1
elif a[i] > b[i]
return 1
.
.
if len a[] < len b[]
return -1
elif len a[] > len b[]
return 1
.
return 0
.
print listcmp [ 2 4 5 ] [ 2 3 1 ]
print listcmp [ 2 3 1 ] [ 2 3 1 ]
print listcmp [ 2 3 1 ] [ 2 3 1 3 ]

## Ela

[] <. _ = true
_ <. [] = false
(x::xs) <. (y::ys) | x == y = xs <. ys
| else   = x < y

[1,2,1,3,2] <. [1,2,0,4,4,0,0,0]

## Elixir

The built-in comparison functions already do this (not only for lists of numbers, but for any arbitrary data type).

iex(1)> [1,2,3] < [1,2,3,4]
true
iex(2)> [1,2,3] < [1,2,4]
true

## Erlang

Builtin. Example use from Erlang shell:

5> [1,2,3] < [1,2,3,4].
true
6> [1,2,3] < [1,2,4].
true

## F#

By using the Collection.Seq Module the static method Seq.compareWith fits our needs.

let inline cmp x y = if x < y then -1 else if x = y then 0 else 1
let before (s1 : seq<'a>) (s2 : seq<'a>) = (Seq.compareWith cmp s1 s2) < 0

[
([0], []);
([], []);
([], [0]);
([-1], [0]);
([0], [0]);
([0], [-1]);
([0], [0; -1]);
([0], [0; 0]);
([0], [0; 1]);
([0; -1], [0]);
([0; 0], [0]);
([0; 0], [1]);
]
|> List.iter (fun (x, y) -> printf "%A %s %A\n" x (if before x y then "< " else ">=") y)
Output:
[0] >= []
[] >= []
[] <  [0]
[-1] <  [0]
[0] >= [0]
[0] >= [-1]
[0] <  [0; -1]
[0] <  [0; 0]
[0] <  [0; 1]
[0; -1] >= [0]
[0; 0] >= [0]
[0; 0] <  [1]

## Factor

All sequences respond to words in the math.order vocabulary.

IN: scratchpad { 2 3 } { 2 5 } before? .
t

## FreeBASIC

Translation of: BBC BASIC
Dim Shared list1(4) As Integer = {1, 2, 1, 5, 2}
Dim Shared list2(5) As Integer = {1, 2, 1, 5, 2, 2}
Dim Shared list3(4) As Integer = {1, 2, 3, 4, 5}
Dim Shared list4(4) As Integer = {1, 2, 3, 4, 5}

Function Orden(listA() As Integer, listB() As Integer) As Boolean
Dim As Integer i = 0, l1, l2
l1 = Ubound(listA, 1)
l2 = Ubound(listB, 1)
While listA(i) = listB(i) And i < l1 And i < l2
i += 1
Wend
If listA(i) < listB(i) Then Return True
If listA(i) > listB(i) Then Return False
Return l1 < l2
End Function

If Orden(list1(), list2()) Then Print "list1<list2" Else Print "list1>=list2"
If Orden(list2(), list3()) Then Print "list2<list3" Else Print "list2>=list3"
If Orden(list3(), list4()) Then Print "list3<list4" Else Print "list3>=list4"

Sleep
Output:
Igual que la entrada de BBC BASIC.

## Go

package main

import "fmt"

// If your numbers happen to be in the range of Unicode code points (0 to 0x10ffff), this function
func lessRune(a, b []rune) bool {
}

// Otherwise, the following function satisfies the task for all integer
// and floating point types, by changing the type definition appropriately.
type numericType int

func lessNT(a, b []numericType) bool {
l := len(a)
if len(b) < l {
l = len(b)
}
for i := 0; i < l; i++ {
if a[i] != b[i] {
return a[i] < b[i]
}
}
return l < len(b)
}

var testCases = [][][]numericType{
{{0}, {}},
{{}, {}},
{{}, {0}},

{{-1}, {0}},
{{0}, {0}},
{{0}, {-1}},

{{0}, {0, -1}},
{{0}, {0, 0}},
{{0}, {0, 1}},
{{0, -1}, {0}},
{{0, 0}, {0}},
{{0, 0}, {1}},
}

func main() {
// demonstrate the general function
for _, tc := range testCases {
fmt.Printf("order %6s before %6s : %t\n",
fmt.Sprintf("%v", tc[0]),
fmt.Sprintf("%v", tc[1]),
lessNT(tc[0], tc[1]))
}
fmt.Println()

// demonstrate that the byte specific function gives identical results
// by offsetting test data to a printable range of characters.
for _, tc := range testCases {
a := toByte(tc[0])
b := toByte(tc[1])
fmt.Printf("order %6q before %6q : %t\n",
string(a),
string(b),
lessByte(a, b))
}
}

func toByte(a []numericType) []byte {
b := make([]byte, len(a))
for i, n := range a {
b[i] = 'b' + byte(n)
}
return b
}
Output:
order    [0] before     [] : false
order     [] before     [] : false
order     [] before    [0] : true
order   [-1] before    [0] : true
order    [0] before    [0] : false
order    [0] before   [-1] : false
order    [0] before [0 -1] : true
order    [0] before  [0 0] : true
order    [0] before  [0 1] : true
order [0 -1] before    [0] : false
order  [0 0] before    [0] : false
order  [0 0] before    [1] : true

order    "b" before     "" : false
order     "" before     "" : false
order     "" before    "b" : true
order    "a" before    "b" : true
order    "b" before    "b" : false
order    "b" before    "a" : false
order    "b" before   "ba" : true
order    "b" before   "bb" : true
order    "b" before   "bc" : true
order   "ba" before    "b" : false
order   "bb" before    "b" : false
order   "bb" before    "c" : true

## Groovy

Solution:

class CList extends ArrayList implements Comparable {
CList() { }
CList(Collection c) { super(c) }
int compareTo(Object that) {
assert that instanceof List
def n = [this.size(), that.size()].min()
def comp = [this[0..<n], that[0..<n]].transpose().find { it[0] != it[1] }
comp ? comp[0] <=> comp[1] : this.size() <=> that.size()
}
}

Test:

CList a, b; (a, b) = [[], []]; assert ! (a < b)
b = [1] as CList;              assert   (a < b)
a = [1] as CList;              assert ! (a < b)
b = [2] as CList;              assert   (a < b)
a = [2, -1, 0] as CList;       assert ! (a < b)
b = [2, -1] as CList;          assert ! (a < b)
b = [2, -1, 0] as CList;       assert ! (a < b)
b = [2, -1, 0, -17] as CList;  assert   (a < b)
a = [2,  8, 0] as CList;       assert ! (a < b)

The built-in comparison operators already do this:

Prelude>  [1,2,1,3,2] < [1,2,0,4,4,0,0,0]
False

## Icon and Unicon

List_llt is written in the style of all Icon/Unicon relational operators returning its right argument if successful and signaling failure otherwise.

procedure main()
write( if list_llt([1,2,1,3,2],[1,2,0,4,4,0,0,0]) then "true" else "false" )
end

procedure list_llt(L1,L2)  #: returns L2 if L1 lexically lt L2 or fails
every i := 1 to min(*L1,*L2) do
if L1[i] << L2[i] then return L2
else if L1[i] >> L2[i] then fail
if *L1 < *L2 then return L2
end

## J

J's built-in comparator operates element-wise. To compare general sequences you can either box them and use sort. Or for numeric sequences append minus infinity and sort. However numeric scalars sort ahead of vectors, i.e. are different from length one lists.

before=: -.@(-: /:~)@,&<~
cmp=: {.@\:@,:&(,&__)

Below demonstrates non-decreasing order cmp treats length one vector same as scalar

cmp&.>"{~ ('';0;(,0);1;(,1);1 1)
┌─┬─┬─┬─┬─┬─┐
011111
├─┼─┼─┼─┼─┼─┤
000111
├─┼─┼─┼─┼─┼─┤
000111
├─┼─┼─┼─┼─┼─┤
000001
├─┼─┼─┼─┼─┼─┤
000001
├─┼─┼─┼─┼─┼─┤
000000
└─┴─┴─┴─┴─┴─┘

before&.>"{~ (0;1;'';(,0);(,1);1 1)
┌─┬─┬─┬─┬─┬─┐
011111
├─┼─┼─┼─┼─┼─┤
001111
├─┼─┼─┼─┼─┼─┤
000111
├─┼─┼─┼─┼─┼─┤
000011
├─┼─┼─┼─┼─┼─┤
000001
├─┼─┼─┼─┼─┼─┤
000000
└─┴─┴─┴─┴─┴─┘

## Java

Works with: Java version 1.5+
Translation of: Common Lisp

There are a few methods here. The method named "ordered" which works on arrays is a translation of Common Lisp. The other two are loose translations of Tcl (some tweaks were needed to get the length checks to work out) and are probably better options.

import java.util.Arrays;
import java.util.List;

public class ListOrder{
public static boolean ordered(double[] first, double[] second){
if(first.length == 0) return true;
if(second.length == 0) return false;
if(first[0] == second[0])
return ordered(Arrays.copyOfRange(first, 1, first.length),
Arrays.copyOfRange(second, 1, second.length));
return first[0] < second[0];
}

public static <T extends Comparable<? super T>> boolean ordered(List<T> first, List<T> second){
int i = 0;
for(; i < first.size() && i < second.size();i++){
int cmp = first.get(i).compareTo(second.get(i));
if(cmp == 0) continue;
if(cmp < 0) return true;
return false;
}
return i == first.size();
}

public static boolean ordered2(double[] first, double[] second){
int i = 0;
for(; i < first.length && i < second.length;i++){
if(first[i] == second[i]) continue;
if(first[i] < second[i]) return true;
return false;
}
return i == first.length;
}
}

## JavaScript

### ES6

<= is already defined for numeric lists in JavaScript

(() => {
'use strict';

// <= is already defined for lists in JS

// compare :: [a] -> [a] -> Bool
const compare = (xs, ys) => xs <= ys;

// TEST
return [
compare([1, 2, 1, 3, 2], [1, 2, 0, 4, 4, 0, 0, 0]),
compare([1, 2, 0, 4, 4, 0, 0, 0], [1, 2, 1, 3, 2])
];

// --> [false, true]
})()
Output:
[false, true]

## Joy

DEFINE order ==
[equal] [false]
[[[[size] dip size <=] [[<=] mapr2 true [and] fold]] [i] map i and]
ifte.

Using it:

[1 2] [1 2 3] order. # true
[1 2] [1 3] order.   # true
[1 2] [1 2] order.   # false
[1 3] [1 2] order.   # false
[1 2 3] [1 2] order. # false

## jq

jq's builtin comparison operators use lexicographic ordering for arrays in general, not just arrays of integers.

[1,2,3] < [1,2,3,4]  # => true
[1,2,3] < [1,2,4]    # => true
[1,2,3] < [1,2,3]    # => false

## Julia

Works with: Julia version 0.6
function islexless(a::AbstractArray{<:Real}, b::AbstractArray{<:Real})
for (x, y) in zip(a, b)
if x == y continue end
return x < y
end
return length(a) < length(b)
end

using Primes, Combinatorics
tests = [[1, 2, 3], primes(10), 0:2:6, [-Inf, 0.0, Inf], [π, e, φ, catalan], [2015, 5], [-sqrt(50.0), 50.0 ^ 2]]
println("List not sorted:\n - ", join(tests, "\n - "))
sort!(tests; lt=islexless)
println("List sorted:\n - ", join(tests, "\n - "))
Output:
List not sorted:
- [1, 2, 3]
- [2, 3, 5, 7]
- 0:2:6
- [-Inf, 0.0, Inf]
- [3.14159, 2.71828, 1.61803, 0.915966]
- [2015, 5]
- [-7.07107, 2500.0]
List sorted:
- [-Inf, 0.0, Inf]
- [-7.07107, 2500.0]
- 0:2:6
- [1, 2, 3]
- [2, 3, 5, 7]
- [3.14159, 2.71828, 1.61803, 0.915966]
- [2015, 5]

## Klingphix

include ..\Utilitys.tlhy

( 1 2 3 ) ( 1 2 3 4 ) less ?
( 1 2 3 4 ) ( 1 2 3 ) less ?
( 1 2 4 ) ( 1 2 3 ) less ?
( 1 2 3 ) ( 1 2 3 ) less ?
( 1 2 3 ) ( 1 2 4 ) less ?

"End " input

## Kotlin

// version 1.0.6

operator fun <T> List<T>.compareTo(other: List<T>): Int
where T: Comparable<T>, T: Number {
for (i in 0 until this.size) {
if (other.size == i) return 1
when {
this[i] < other[i] -> return -1
this[i] > other[i] -> return 1
}
}
return if (this.size == other.size) 0 else -1
}

fun main(args: Array<String>) {
val lists = listOf(
listOf(1, 2, 3, 4, 5),
listOf(1, 2, 1, 5, 2, 2),
listOf(1, 2, 1, 5, 2),
listOf(1, 2, 1, 5, 2),
listOf(1, 2, 1, 3, 2),
listOf(1, 2, 0, 4, 4, 0, 0, 0),
listOf(1, 2, 0, 4, 4, 1, 0, 0)
)
for (i in 0 until lists.size) println("list\${i + 1} : \${lists[i]}")
println()
for (i in 0 until lists.size - 1) println("list\${i + 1} > list\${i + 2} = \${lists[i] > lists[i + 1]}")
}
Output:
list1 : [1, 2, 3, 4, 5]
list2 : [1, 2, 1, 5, 2, 2]
list3 : [1, 2, 1, 5, 2]
list4 : [1, 2, 1, 5, 2]
list5 : [1, 2, 1, 3, 2]
list6 : [1, 2, 0, 4, 4, 0, 0, 0]
list7 : [1, 2, 0, 4, 4, 1, 0, 0]

list1 > list2 = true
list2 > list3 = true
list3 > list4 = false
list4 > list5 = true
list5 > list6 = true
list6 > list7 = false

## LabVIEW

Translation of: AutoHotkey

This image is a VI Snippet, an executable image of LabVIEW code. The LabVIEW version is shown on the top-right hand corner. You can download it, then drag-and-drop it onto the LabVIEW block diagram from a file browser, and it will appear as runnable, editable code.

## Lasso

This is built into the Lasso comparison operators

local(
first = array(1,2,1,3,2),
second = array(1,2,0,4,4,0,0,0),
)
#first < #second

local(
first = array(1,1,1,3,2),
second = array(1,2,0,4,4,0,0,0),
)
#first < #second
Output:
false
true

## Lhogho

Uses standard '=' notation

print [1 2] = [1 2]
print [1 2] = [1 2 3]
print [1 3] = [1 2]
print [1 2 3] = [1 2]

make "list1 [1 2 3 4 5 6]
make "list2 [1 2 3 4 5 7]
print :list1 = :list2
Output:
true
false
false
false
false

## Lua

In Lua tables with numerical indices are used as lists or arrays and they do not support comparison out-of-the-box, so a function is needed to implement the comparison:

function arraycompare(a, b)
for i = 1, #a do
if b[i] == nil then
return true
end
if a[i] ~= b[i] then
return a[i] < b[1]
end
end
return true
end

Here is some demonstration code:

function randomarray()
local t = {}
for i = 1, math.random(1, 10) do
t[i] = math.random(1, 10)
end
return t
end

math.randomseed(os.time())

for i = 1, 10 do
local a = randomarray()
local b = randomarray()

print(
string.format("{%s} %s {%s}",
table.concat(a, ', '),
arraycompare(a, b) and "<=" or ">",
table.concat(b, ', ')))
end
Output:

(time used as random seed

1413127434):
{10, 7, 4, 9, 10, 3, 5, 5, 5, 5} > {7, 4, 6, 4, 3, 5, 10}
{5, 7} <= {6, 3, 7, 7, 7, 1}
{4} <= {10, 10, 3, 8, 10, 5, 2, 5, 10, 6}
{6} <= {6, 10, 2, 1, 9, 4, 5, 6, 9}
{9, 5, 7, 5, 5, 7, 9, 5, 6, 8} > {4, 7, 3, 5, 1, 2, 1, 2}
{10, 8, 6, 1, 8, 5, 4} > {1, 2}
{9, 7} > {4, 1, 5, 2, 6, 1, 9, 3, 5}
{5, 9, 7, 6, 10, 8} <= {9, 6, 9}
{4, 3, 4, 6, 3, 6, 7, 2, 2, 5} > {3, 10, 6, 8, 1}
{1, 5, 1, 5, 4} > {1, 3, 5, 3, 2, 10, 1}

## Maple

orderLists := proc(num1,num2)
local len1, len2,i:
len1,len2 := numelems(num1),numelems(num2):
for i to min(len1,len2) do
if num1[i] <> num2[i] then
return evalb(num1[i]<num2[i]):
end if:
end do:
return evalb(len1 < len2):
end proc:

## Mathematica /Wolfram Language

order[List1_, List2_] := With[{
L1 = List1[[1 ;; Min @@ Length /@ {List1, List2}]],
L2 = List2[[1 ;; Min @@ Length /@ {List1, List2}]]
},
Length[List1] < Length[List2],
]]
Example use:
order[ {1, 2, 1, 3, 2}, {1, 2, 0, 4, 4, 0, 0, 0} ]
->False
order[ {1, 2}, {1, 2, 4, 4, 0, 0} ]
->True

## Maxima

"<<"(a,b):=block([n:min(length(a),length(b))],
catch(for i thru n do (if a[i]#b[i] then throw(is(a[i]<b[i]))),
throw(is(length(a)<length(b)))))\$
infix("<<")\$

[1,2,3] << [1,2,4];
true

[1,2,3] << [1,2];
false

[1,2] << [1,2];
false

## Mercury

For a particular numerical type, you can get away with

:- pred lt(list(int)::in, list(int)::in) is semidet.
lt([], [_|_]).
lt([H1|T1], [H2|T2]) :- H1 =< H2, T1 `lt` T2.

For a list of any numerical type, one way would be to use a typeclass:

:- pred lt(list(T)::in, list(T)::in) is semidet <= comparable(T).
lt([], [_|_]).
lt([H1|T1], [H2|T2]) :- H1 =< H2, T1 `lt` T2.

... which you would have to create:

:- module comparable.
:- interface.
:- import_module int, float, integer, list.

:- typeclass comparable(T) where [
pred '<'(T::in, T::in) is semidet,
pred '=<'(T::in, T::in) is semidet
].
:- instance comparable(int).
:- instance comparable(float).
:- instance comparable(integer).
:- instance comparable(list(T)) <= comparable(T).

:- implementation.

:- instance comparable(int) where [
pred('<'/2) is int.(<),
pred('=<'/2) is int.(=<)
].
% likewise for float and integer...
:- instance comparable(list(T)) <= comparable(T) where [
pred('<'/2) is lt,   % the 'lt' above.
pred('=<'/2) is lte  % 'lt' with: lte([], []).
].

% pred lt
% pred lte

Which would be used in this way - note the typeclass and the comparison operator.

:- pred test(list(T), list(T), io, io) <= comparable(T).
:- mode test(in, in, di, uo) is det.
test(A, B) -->
io.write(A), io.write_string(" < "), io.write(B),
io.write_string(" : "), io.write_string(S), io.nl,
{ A < B -> S = "yes" ; S = "no" }.

## Miranda

main :: [sys_message]
main = [Stdout (lay (map show [
order [1,2,1,3,2] [1,2,0,4,4,0,0,0],
order [1,2,0,4,4,0,0,0] [1,2,1,3,2]]))]

order :: [*]->[*]->bool
order as     []     = True
order []     as     = False
order (a:as) (b:bs) = a < b, if a ~= b
= order as bs, otherwise
Output:
False
True

## Nim

proc `<`[T](a, b: openarray[T]): bool =
for i in 0 .. min(a.len, b.len):
if a[i] < b[i]: return true
if a[i] > b[i]: return false
return a.len < b.len

echo([1,2,1,3,2] < [1,2,0,4,4,0,0,0])
Output:
false

## OCaml

The built-in comparison operators already do this for lists (although this is not documented):

# [1;2;1;3;2] < [1;2;0;4;4;0;0;0];;
- : bool = false

(Warning: However, the built-in comparison operators do not do this for arrays:

# [|1;2;1;3;2|] < [|1;2;0;4;4;0;0;0|];;
- : bool = true

)

But we could write it explicitly this way:

let rec ordered_lists = function
| x1::tl1, x2::tl2 ->
(match compare x1 x2 with
| 0 -> ordered_lists (tl1, tl2)
| 1 -> false
| _ -> true)
| [], _ -> true
| _ -> false

Here is a small script to test this function:

(* copy-paste the code of ordered_lists here *)

let make_num_list p n =
let rec aux acc =
if Random.int p = 0 then acc
else aux (Random.int n :: acc)
in
aux []

let print_num_list lst =
List.iter (Printf.printf " %d") lst;
print_newline()

let () =
Random.self_init();
let lst1 = make_num_list 8 5 in
let lst2 = make_num_list 8 5 in
print_num_list lst1;
print_num_list lst2;
Printf.printf "ordered: %B\n" (ordered_lists (lst1, lst2))

Sample execution:

\$ ocaml ordered_lists.ml
1 2 1 3 2
1 2 0 4 4 0 0 0
ordered: false

Also notice that the function ordered_lists will work with anything the function Pervasives.compare is able to compare (most OCaml types and structures made from the base types). In the prototype of this function below 'a list means a list of anything:

val ordered_lists : 'a list * 'a list -> bool

## Oforth

In Oforth, list comparison is already defined.

Output:
[1,2,0,4,4,0,0,0] [1,2,1,3,2] <= .
1 ok

## Ol

This sample very similar to Scheme, but implements proper tail recursion. So can test unlimited length lists.

(define (lexorder a b)
(cond
((null? b) #false)
((null? a) #true)
((< (car a) (car b)) #true)
((> (car a) (car b)) #false)
(else
(lexorder (cdr a) (cdr b)))))

(print (lexorder '(1 2 3) '(1 2 3 4))) ; => true
(print (lexorder '(1 2 4) '(1 2 3)))   ; => false
(print (lexorder '(1 2 3) '(1 2)))     ; => false
(print (lexorder '(1 2 3) '(1 2 3)))   ; => false
(print (lexorder '(1 2 3) '(1 2 8)))   ; => true

lex(u,v)<1

## Perl

use strict;
use warnings;

sub orderlists {
my (\$firstlist, \$secondlist) = @_;

my (\$first, \$second);
while (@{\$firstlist}) {
\$first = shift @{\$firstlist};
if (@{\$secondlist}) {
\$second = shift @{\$secondlist};
if (\$first < \$second) {
return 1;
}
if (\$first > \$second) {
return 0;
}
}
else {
return 0;
}
}

@{\$secondlist} ? 1 : 0;
}

foreach my \$pair (
[[1, 2, 4], [1, 2, 4]],
[[1, 2, 4], [1, 2,  ]],
[[1, 2,  ], [1, 2, 4]],
[[55,53,1], [55,62,83]],
[[20,40,51],[20,17,78,34]],
) {
my \$first  = \$pair->[0];
my \$second = \$pair->[1];
my \$before = orderlists([@\$first], [@\$second]) ? 'true' : 'false';
print "(@\$first) comes before (@\$second) : \$before\n";
}
Output:
(1 2 4) comes before (1 2 4) : false
(1 2 4) comes before (1 2) : false
(1 2) comes before (1 2 4) : true
(55 53 1) comes before (55 62 83) : true
(20 40 51) comes before (20 17 78 34) : false

## Phix

Handled natively, eg ("?" is the shorthand print operator)

with javascript_semantics
?{1,2,3}<{1,2,3,4}  -- 1 (true under p2js)
?{1,2,3,4}<{1,2,3}  -- 0 (false "")
?{1,2,4}<{1,2,3}    -- 0 (false "")
?{1,2,3}<{1,2,3}    -- 0 (false "")
?{1,2,3}<{1,2,4}    -- 1 (true "")

Elements can be any mix of integers, floating point numbers, strings, or nested subsequences, with atoms ordered before sequences.
If you want -1/0/+1 (instead of the true(1)/false(0) shown above), use the builtin compare() function, and that will match under p2js.

## Phixmonti

Translation of: Phix
include Utilitys.pmt

def ? print nl enddef

( 1 2 3 ) ( 1 2 3 4 ) < ?
( 1 2 3 4 ) ( 1 2 3 ) < ?
( 1 2 4 ) ( 1 2 3 ) < ?
( 1 2 3 ) ( 1 2 3 ) < ?
( 1 2 3 ) ( 1 2 4 ) < ?

## Picat

Picat has a built-in general comparison operator @<, which compares terms in lexicographic order (numeric lists as well as atoms, strings, variables, and structures).

go =>
Tests = [
[[1,2,3], [1,2,3]],
[[1,2,3], [1,2,3,4]],
[[1,2,2], [1,2,3]],
[[1,2,4], [1,2,3]],
[1..10  , 1..8],
[[]     , []],
[[]     , [1]],
[[1]    , [] ],
[[-1,2,3,6,5],[-1,2,3,5,6]],
[[-1,2,3,-5,6],[-1,2,3,-6,5]]
],
foreach([L1,L2] in Tests)
printf("%w @< %w: %w\n",L1,L2,cond(L1 @< L2,true,false))
end,
nl.

In the Picat shell, the result is yes/no rather than true/false:

Picat> [1,2,3] @< [1,2,3]

no

Picat> [1,2,3] @< [1,2,3,4]

yes

## PicoLisp

The built-in comparison functions already do this (not only for lists of numbers, but for any arbitrary data type).

: (> (1 2 0 4 4 0 0 0) (1 2 1 3 2))
-> NIL

## Pike

int(0..1) order_array(array a, array b)
{
if (!sizeof(a)) return true;
if (!sizeof(b)) return false;
if (a[0] == b[0])
return order_array(a[1..], b[1..]);
return a[0] < b[0];
}

Pikes Array.sort_array() function can sort an array of arrays using the < operator, but it will sort longer arrays before shorter ones. Therefore the above function is still needed if the intent is to use the comparison for a sort operation.

If the numbers are in 32bit signed integer range, the following works too:

(string)a < (string)b;

## PL/I

lists: procedure options (main);  /* 8 June 2014 */

declare a(10) fixed initial (1, 2, 3, 4, 5, 8, 9, 10, 16, 17),
b(15) fixed initial (5, 6, 7, 8, 9, 10, 11, 12, 15, 16, 17, 18, 20, 22, 23);

put skip list (compare(a, b));
put skip list (compare(b, a));
put skip list (compare(a, a));

compare: procedure (a, b) returns (bit (1));
declare (a, b)(*) fixed;
declare (i, m, n) fixed binary;

m = hbound(a,1); n = hbound(b,1);
do i = 1 to min(m, n);
return (a(i) < b(i));
end;
return (m < n);
end compare;

end lists;

Results:

'1'B    (true)
'0'B    (false)
'0'B

## PowerShell

function  order(\$as,\$bs) {
if(\$as -and \$bs) {
\$a, \$as = \$as
\$b, \$bs = \$bs
if(\$a -eq \$b) {order \$as \$bs}
else{\$a -lt \$b}
} elseif (\$bs) {\$true} else {\$false}
}
"\$(order @(1,2,1,3,2) @(1,2,0,4,4,0,0,0))"

Output:

False

### Non-Recursive Version

function Test-Order ([int[]]\$ReferenceArray, [int[]]\$DifferenceArray)
{
for (\$i = 0; \$i -lt \$ReferenceArray.Count; \$i++)
{
if (\$ReferenceArray[\$i] -lt \$DifferenceArray[\$i])
{
return \$true
}
elseif (\$ReferenceArray[\$i] -gt \$DifferenceArray[\$i])
{
return \$false
}
}

return (\$ReferenceArray.Count -lt \$DifferenceArray.Count) -or (Compare-Object \$ReferenceArray \$DifferenceArray) -eq \$null
}
Test-Order -ReferenceArray 1, 2, 1, 3, 2 -DifferenceArray 1, 2, 0, 4, 4, 0, 0, 0
Test-Order -ReferenceArray 1, 2, 1, 3, 2 -DifferenceArray 1, 2, 2, 4, 4, 0, 0, 0
Test-Order -ReferenceArray 1, 2, 3       -DifferenceArray 1, 2
Test-Order -ReferenceArray 1, 2          -DifferenceArray 1, 2, 3
Test-Order -ReferenceArray 1, 2          -DifferenceArray 1, 2
Output:
False
True
False
True
True

## PureBasic

DataSection
Array_1:
Data.i 5              ;element count
Data.i 1, 2, 3, 4, 5  ;element data
Array_2:
Data.i 6
Data.i 1, 2, 1, 5, 2, 2
Array_3:
Data.i 5
Data.i 1, 2, 1, 5, 2
Array_4:
Data.i 5
Data.i 1, 2, 1, 5, 2
Array_5:
Data.i 4
Data.i 1, 2, 1, 6
Array_6:
Data.i 5
Data.i 1, 2, 1, 6, 2
EndDataSection

#False = 0
#True = 1

;helper subrountine to initialize a dataset, *dataPtr points to the elementcount followed by the element data
Procedure initArrayData(Array a(1), *dataPtr)
Protected elementCount = PeekI(*dataPtr)

Dim a(elementCount - 1)
For i = 0 To elementCount - 1
*dataPtr + SizeOf(Integer)
a(i) = PeekI(*dataPtr)
Next
EndProcedure

;helper subroutine that returns 'True' or 'False' for a boolean input
Procedure.s booleanText(b)
If b: ProcedureReturn "True": EndIf
ProcedureReturn "False"
EndProcedure

Procedure order(Array a(1), Array b(1))
Protected len_a = ArraySize(a()), len_b = ArraySize(b()), elementIndex

While elementIndex <= len_a And elementIndex <= len_b And a(elementIndex) = b(elementIndex)
elementIndex + 1
Wend

If (elementIndex > len_a  And elementIndex <= len_b) Or (elementIndex <= len_b And a(elementIndex) <= b(elementIndex))
ProcedureReturn #True
EndIf
EndProcedure

Dim A_1(0): initArrayData(A_1(), ?Array_1)
Dim A_2(0): initArrayData(A_2(), ?Array_2)
Dim A_3(0): initArrayData(A_3(), ?Array_3)
Dim A_4(0): initArrayData(A_4(), ?Array_4)
Dim A_5(0): initArrayData(A_5(), ?Array_5)
Dim A_6(0): initArrayData(A_6(), ?Array_6)

If OpenConsole()
PrintN(booleanText(order(A_1(), A_2()))) ;False
PrintN(booleanText(order(A_2(), A_3()))) ;False
PrintN(booleanText(order(A_3(), A_4()))) ;False
PrintN(booleanText(order(A_4(), A_5()))) ;True
PrintN(booleanText(order(A_5(), A_6()))) ;True

Print(#crlf\$ + #crlf\$ + "Press ENTER to exit"): Input()
CloseConsole()
EndIf
Output:
False
False
False
True
True

## Python

The built-in comparison operators already do this:

>>> [1,2,1,3,2] < [1,2,0,4,4,0,0,0]
False

## Quackery

[ [ over [] = iff false done
dup  [] = iff true done
2dup = iff
[ 2drop swap ] again
> ]
unrot 2drop ]               is []< ( [ [ --> b )

' [ [ ] [ 1 ] [ 1 1 1 ] [ 1 2 ] [ 1 2 1 ] [ 2 ] [ 2 1 ] [ 2 1 1 ] ]

shuffle sortwith []< echo
Output:
[ [ ] [ 1 ] [ 1 1 1 ] [ 1 2 ] [ 1 2 1 ] [ 2 ] [ 2 1 ] [ 2 1 1 ] ]

## Racket

#lang racket

(define (lex<? a b)
(cond ((null? b) #f)
((null? a) #t)
((= (car a) (car b)) (lex<? (cdr a) (cdr b)))
(else (< (car a) (car b)))))

(lex<? '(1 2 3 4 5) '(1 2 3 4 4)) ; -> #f

## Raku

(formerly Perl 6) There is already a built-in comparison operator.

my @a = <1 2 4>;
my @b = <1 2 4>;
say @a," before ",@b," = ", @a before @b;

@a = <1 2 4>;
@b = <1 2>;
say @a," before ",@b," = ", @a before @b;

@a = <1 2>;
@b = <1 2 4>;
say @a," before ",@b," = ", @a before @b;

for 1..10 {
my @a = flat (^100).roll((2..3).pick);
my @b = flat @a.map: { Bool.pick ?? \$_ !! (^100).roll((0..2).pick) }
say @a," before ",@b," = ", @a before @b;
}
Output:
1 2 4 before 1 2 4 = False
1 2 4 before 1 2 = False
1 2 before 1 2 4 = True
63 52 before 0 52 = False
17 75 24 before 31 75 24 = True
43 32 before 43 32 = False
73 84 before 2 84 = False
73 92 before 40 24 46 = False
16 24 before 41 24 = True
9 12 22 before 9 12 32 67 = True
81 23 before 81 23 = False
55 53 1 before 55 62 83 = True
20 40 51 before 20 17 78 34 = False

## Rascal

The built-in comparison operator already does this:

rascal>[2,1,3] < [5,2,1,3]
bool: true

## REXX

This REXX example uses the same lists as   BBC BASIC.

This example will also work with non-numeric strings.

/*REXX program determines  if  a list < previous list,   and returns   true  or  false. */
@.=;                    @.1 = 1 2 1 5 2
@.2 = 1 2 1 5 2 2
@.3 = 1 2 3 4 5
@.4 = 1 2 3 4 5
/* [↓]  compare a list to previous list*/
do j=2  while  @.j\=='';      p= j - 1  /*P:  points to previous value in list.*/
if FNorder(@.p, @.j)=='true'  then is= " < "       /*use a more familiar glyph.*/
else is= " ≥ "       /* "  "   "      "      "   */
say
say right('['@.p"]", 40)  is  '['@.j"]"
end   /*i*/
exit                                             /*stick a fork in it,  we're all done. */
/*──────────────────────────────────────────────────────────────────────────────────────*/
FNorder: procedure;  parse arg x,y
wx= words(x);     wy= words(y)
do k=1  for min(wx, wy)
a= word(x, k)         /*get a value from X. */
b= word(y, k)         /* "  "   "     "  Y. */
if a<b  then                return 'true'
else  if a>b  then  return 'false'
end   /*k*/
if wx<wy  then return 'true'                  /*handle case of equal (so far). */
return 'false'                 /*   "     "   "   "     "   "   */
output:
[1 2 1 5 2]  <  [1 2 1 5 2 2]

[1 2 1 5 2 2]  <  [1 2 3 4 5]

[1 2 3 4 5]  ≥  [1 2 3 4 5]

## Ring

list1 = "1, 2, 1, 5, 2"
list2 = "5, 2, 1, 5, 2, 2"
list3 = "1, 2, 3, 4, 5"
list4 = "1, 2, 3, 4, 5"

if order(list1, list2) = 0 see "list1=list2" + nl
but order(list1, list2) < 0 see "list1<list2" + nl
else see "list1>list2" + nl ok

if order(list2, list3) = 0 see "list2=list3" + nl
but order(list2, list3) < 0 see "list2<list3" + nl
else see "list2>list3" + nl ok

if order(list3, list4) = 0 see "list3=list4" + nl
but order(list3, list4) < 0 see "list3<list4" + nl
else see "list3>list4" + nl ok

func order alist, blist
return strcmp(alist, blist)

Output:

list1<list2
list2>list3
list3=list4

## RPL

Works with: HP version 28
RPL code Comment
≪ → a b
≪ a SIZE b SIZE MIN LAST <
1 ROT FOR j
IF b j GET a j GET - THEN
LAST 0 > SWAP DROP
a SIZE 'j' STO
END
NEXT
≫ ≫ ‘GR8R?’ STO
GR8R? ( [reals] [reals] → boolean )
m = min(size(a),size(b)) ; res = (size(a)<size(b))
loop for j=1 to m
if b[j]-a[j] ≠ 0
res = (b[j]-a[j]>0)
break
end if
end loop, return res
.
[1 2 1 5 2]    [1 2 1 5 2 2] GR8R?
[1 2 1 5 2 2]  [1 2 1 5 2] GR8R?
[1 2 1 5 2 2]  [1 2 3 4 5] GR8R?
[1 2 3 4 5]    [1 2 1 5 2 2] GR8R?
[1 2 3 4 5]    [1 2 3 4 5] GR8R?
Output:
5: 1
4: 0
3: 1
2: 0
1: 0

## Ruby

The built-in <=> operator already does this:

>> ([1,2,1,3,2] <=> [1,2,0,4,4,0,0,0]) < 0
=> false

## Rust

Vec<T> implements Ord when T does, so we can just compare them with <. (Same with arrays and slices).

vec![1, 2, 1, 3, 2] < vec![1, 2, 0, 4, 4, 0, 0, 0]

## Scala

def lessThan1(a: List[Int], b: List[Int]): Boolean =
if (b.isEmpty) false
else if (a.isEmpty) true
else lessThan1(a.tail, b.tail)
def lessThan2(a: List[Int], b: List[Int]): Boolean = (a, b) match {
case (_, Nil) => false
case (Nil, _) => true
case (a :: _, b :: _) if a != b => a < b
case _ => lessThan2(a.tail, b.tail)
}
def lessThan3(a: List[Int], b: List[Int]): Boolean =
a.zipAll(b, Integer.MIN_VALUE, Integer.MIN_VALUE)
.find{case (a, b) => a != b}
.map{case (a, b) => a < b}
.getOrElse(false)
val tests = List(
(List(1, 2, 3), List(1, 2, 3)) -> false,
(List(3, 2, 1), List(3, 2, 1)) -> false,
(List(1, 2, 3), List(3, 2, 1)) -> true,
(List(3, 2, 1), List(1, 2, 3)) -> false,
(List(1, 2), List(1, 2, 3)) -> true,
(List(1, 2, 3), List(1, 2)) -> false
)

tests.foreach{case test @ ((a, b), c) =>
assert(lessThan1(a, b) == c, test)
assert(lessThan2(a, b) == c, test)
assert(lessThan3(a, b) == c, test)
}

## Scheme

(define (lex<? a b)
(cond ((null? b) #f)
((null? a) #t)
((= (car a) (car b)) (lex<? (cdr a) (cdr b)))
(else (< (car a) (car b)))))

## Seed7

The operator corresponding to the ordering described in this example is less than.

\$ include "seed7_05.s7i";

const proc: main is func
begin
writeln([] (1)       < [] (1, 2));    # If the first list runs out of elements the result is TRUE.
writeln([] (1, 2)    < [] (1));       # If the second list runs out of elements the result is FALSE.
writeln([] (1, 2)    < [] (1, 2));    # If both lists run out of elements the result is FALSE.
writeln([] (1, 2, 3) < [] (1, 1, 3)); # The second element is greater than --> FALSE
writeln([] (1, 2, 3) < [] (1, 3, 3)); # The second element is less than --> TRUE
writeln(0 times 0    < [] (1));       # The empty list is less than any nonempty list --> TRUE
writeln([] (1)       < 0 times 0);    # Any nonempty list is not less than the empty list --> FALSE
writeln(0 times 0    < 0 times 0);    # The empty list is not less than the empty list --> FALSE
end func;
Output:
TRUE
FALSE
FALSE
FALSE
TRUE
TRUE
FALSE
FALSE

## Sidef

Built-in, via the comparison operator (`<=>`):

func ordered(a, b) {
(a <=> b) < 0
}

for p in [
Pair([1,2,4], [1,2,4]),
Pair([1,2,4], [1,2]  ),
Pair([1,2],   [1,2,4]),
] {
var a = p.first
var b = p.second
var before = ordered(a, b)
say "#{a} comes before #{b} : #{before}"
}
Output:
[1, 2, 4] comes before [1, 2, 4] : false
[1, 2, 4] comes before [1, 2] : false
[1, 2] comes before [1, 2, 4] : true

## Standard ML

- List.collate Int.compare ([1,2,1,3,2], [1,2,0,4,4,0,0,0]) = LESS;
val it = false : bool

## Swift

let a = [1,2,1,3,2]
let b = [1,2,0,4,4,0,0,0]
println(lexicographicalCompare(a, b)) // this is "less than"
Output:
false

## Tcl

proc numlist< {A B} {
foreach a \$A b \$B {
if {\$a<\$b} {
return 1
} elseif {\$a>\$b} {
return 0
}
}
return 0
}

## TUSCRIPT

\$\$ MODE TUSCRIPT
MODE DATA
\$\$ numlists=*
1'2'1'3'2
1'2'0'4'4'0'0'0
1'2'3'4'5
1'2'1'5'2'2
1'2'1'6
1'2'1'6'2
1'2'4
1'2'4
1'2
1'2'4
\$\$ MODE TUSCRIPT
list1="1'2'5'6'7"
LOOP n,list2=numlists
text=CONCAT (" ",list1," < ",list2)
IF (list1<list2) THEN
PRINT " true: ",text
ELSE
PRINT "false: ",text
ENDIF
list1=VALUE(list2)
ENDLOOP
Output:
false:  1'2'5'6'7 < 1'2'1'3'2
false:  1'2'1'3'2 < 1'2'0'4'4'0'0'0
true:  1'2'0'4'4'0'0'0 < 1'2'3'4'5
false:  1'2'3'4'5 < 1'2'1'5'2'2
true:  1'2'1'5'2'2 < 1'2'1'6
true:  1'2'1'6 < 1'2'1'6'2
true:  1'2'1'6'2 < 1'2'4
false:  1'2'4 < 1'2'4
false:  1'2'4 < 1'2
true:  1'2 < 1'2'4

## VBA

Private Function order(list1 As Variant, list2 As Variant) As Boolean
i = 1
Do While list1(i) <= list2(i)
i = i + 1
If i > UBound(list1) Then
order = True
Exit Function
End If
If i > UBound(list2) Then
order = False
Exit Function
End If
Loop
order = False
End Function
Public Sub main()
Debug.Print order([{1, 2, 3, 4}], [{1,2,0,1,2}])
Debug.Print order([{1, 2, 3, 4}], [{1,2,3}])
Debug.Print order([{1, 2, 3}], [{1,2,3,4}])
End Sub
Output:
Onwaar
Onwaar
Waar

## VBScript

Function order_list(arr1,arr2)
order_list = "FAIL"
n1 = UBound(arr1): n2 = UBound(arr2)
n = 0 : p = 0
If n1 > n2 Then
max = n2
Else
max = n1
End If
For i = 0 To max
If arr1(i) > arr2(i) Then
n = n + 1
ElseIf arr1(i) = arr2(i) Then
p = p + 1
End If
Next
If (n1 < n2 And n = 0) Or _
(n1 = n2 And n = 0 And p - 1 <> n1) Or _
(n1 > n2 And n = 0 And p = n2) Then
order_list = "PASS"
End If
End Function

WScript.StdOut.WriteLine order_list(Array(-1),Array(0))
WScript.StdOut.WriteLine order_list(Array(0),Array(0))
WScript.StdOut.WriteLine order_list(Array(0),Array(-1))
WScript.StdOut.WriteLine order_list(Array(0),Array(0,-1))
WScript.StdOut.WriteLine order_list(Array(0),Array(0,0))
WScript.StdOut.WriteLine order_list(Array(0),Array(0,1))
WScript.StdOut.WriteLine order_list(Array(0,-1),Array(0))
WScript.StdOut.WriteLine order_list(Array(0,0),Array(0))
WScript.StdOut.WriteLine order_list(Array(0,0),Array(1))
WScript.StdOut.WriteLine order_list(Array(1,2,1,3,2),Array(1,2,0,4,4,0,0,0))
Output:
PASS
FAIL
FAIL
PASS
PASS
PASS
FAIL
FAIL
PASS
FAIL

## Wart

We'll simply overload < for lists.

def (a < b) :case (or list?.a list?.b)
if not.b
nil
not.a
b
(car.a = car.b)
(cdr.a < cdr.b)
:else
(car.a < car.b)
Output:
(< '(1 2 3) '(1 2 4))
=> 4
(< '(1 2 4) '(1 2 3))
=> nil

(< '(1 2 3) '(1 2 3 4))
=> (4)
(< '(1 2 4) '(1 2 3 4))
=> nil

## Wren

var orderLists = Fn.new { |l1, l2|
var len = (l1.count <= l2.count) ? l1.count : l2.count
for (i in 0...len) {
if (l1[i] < l2[i]) return true
if (l1[i] > l2[i]) return false
}
return (l1.count < l2.count)
}

var lists = [
[1, 2, 3, 4, 5],
[1, 2, 1, 5, 2, 2],
[1, 2, 1, 5, 2],
[1, 2, 1, 5, 2],
[1, 2, 1, 3, 2],
[1, 2, 0, 4, 4, 0, 0, 0],
[1, 2, 0, 4, 4, 1, 0, 0],
[1, 2, 0, 4, 4, 1, 0, 1]
]

for (i in 0...lists.count) System.print("list[%(i)] : %(lists[i])")
System.print()
for (i in 0...lists.count-1) {
var res = orderLists.call(lists[i], lists[i+1])
System.print("list[%(i)] < list[%(i+1)] -> %(res)")
}
Output:
list[0] : [1, 2, 3, 4, 5]
list[1] : [1, 2, 1, 5, 2, 2]
list[2] : [1, 2, 1, 5, 2]
list[3] : [1, 2, 1, 5, 2]
list[4] : [1, 2, 1, 3, 2]
list[5] : [1, 2, 0, 4, 4, 0, 0, 0]
list[6] : [1, 2, 0, 4, 4, 1, 0, 0]
list[7] : [1, 2, 0, 4, 4, 1, 0, 1]

list[0] < list[1] -> false
list[1] < list[2] -> false
list[2] < list[3] -> false
list[3] < list[4] -> false
list[4] < list[5] -> false
list[5] < list[6] -> true
list[6] < list[7] -> true

## XPL0

Translation of: ALGOL W
\Compare lists (rows) of integers.
\Returns TRUE if there is an element in A that is < the corresponding
\ element in B and all previous elements are equal, FALSE otherwise.
\The bounds of A and B should ALB :: AUB and BLB :: BUB.
function ILT ( A, ALB, AUB, B, BLB, BUB );
integer  A, ALB, AUB, B, BLB, BUB;
integer  APos, BPos, Equal;
begin
APos := ALB;
BPos := BLB;
Equal := true;
while APos <= AUB and BPos <= BUB and Equal do begin
Equal := A( APos ) = B( BPos );
if Equal then begin
APos := APos + 1;
BPos := BPos + 1
end \if_Equal
end; \while_more_elements_and_Equal
if not Equal
then \there is an element in A and B that is not Equal
return A( APos ) < B( BPos )
else \all elements are Equal or one list is shorter
\A is < B if A has fewer elements
return APos > AUB and BPos <= BUB
end; \ILT

\Tests A < B has the expected result
procedure Test ( AName, A, ALB, AUB, BName, B, BLB, BUB, Expected );
integer   AName, A, ALB, AUB, BName, B, BLB, BUB, Expected;
integer   IsLt;
begin
IsLt := ILT( A, ALB, AUB, B, BLB, BUB );
Text(0, AName);
Text(0, if IsLt then " <  " else " >= ");
Text(0, BName);
Text(0, if IsLt = Expected then " " else ", NOT as expected");
CrLf(0);
end; \test

integer List1, List2, List3, List4, List5, List6, List7, List8;
begin
\test cases as in the BBC basic sample
List1 := [0, 1, 2, 1, 5, 2];
List2 := [0, 1, 2, 1, 5, 2, 2];
List3 := [0, 1, 2, 3, 4, 5];
List4 := [0, 1, 2, 3, 4, 5];
Test( "List1", List1, 1, 5, "List2", List2, 1, 6, true  );
Test( "List2", List2, 1, 6, "List3", List3, 1, 5, true  );
Test( "List3", List3, 1, 5, "List4", List4, 1, 5, false );
List5 := [0, 9, 0, 2, 1, 0];
List6 := [0, 4, 0, 7, 7];
List7 := [0, 4, 0, 7];
List8 := [0, 0];
Test( "List5", List5, 1, 5, "List6", List6, 1, 4, false );
Test( "List6", List6, 1, 4, "List7", List7, 1, 3, false );
Test( "List7", List7, 1, 3, "List8", List8, 1, 0, false );
Test( "List8", List8, 1, 0, "List7", List7, 1, 3, true  )
end
Output:
List1 <  List2
List2 <  List3
List3 >= List4
List5 >= List6
List6 >= List7
List7 >= List8
List8 <  List7

## Yabasic

Translation of: FreeBASIC

if Orden(list1(), list2()) then print "list1 < list2" else print "list1 >= list2" : fi
if Orden(list2(), list3()) then print "list2 < list3" else print "list2 >= list3" : fi
if Orden(list3(), list4()) then print "list3 < list4" else print "list3 >= list4" : fi
end

sub Orden(listA(), listB())
i = 0
l1 = arraysize(listA(), 1)
l2 = arraysize(listB(), 1)
while listA(i) = listB(i) and i < l1 and i < l2
i = i + 1
wend
if listA(i) < listB(i) then return True : fi
if listA(i) > listB(i) then return False : fi
return l1 < l2
end sub

data  1, 2, 1, 5, 2
data  1, 2, 1, 5, 2, 2
data  1, 2, 3, 4, 5
data  1, 2, 3, 4, 5
Output:
Igual que la entrada de BBC BASIC.

## zkl

fcn listLT(a,b){
a.walker().zip(b).filter1(fcn([(a,b)]){ a<b }) :  // lazy
if(_) return(True);;
a.len()<b.len()
}
Output:
listLT(T(1,2,3),T(2,3,4)).println();   //-->True
listLT(T(2,3,4),T(1,2,3)).println();   //-->False
listLT(T(1,2),T(1,2,3,4)).println();   //-->True
listLT(T(1,2,3,4),T(1,2,3)).println(); //-->False
listLT(T(1,2,3),T(1,2,3)).println();   //-->False