Order two numerical lists
From Rosetta Code
You are encouraged to solve this task according to the task description, using any language you may know.
Write 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.
[edit] 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
[edit] Ada
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:
with Ada.Text_IO; use Ada.Text_IO;
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
[edit] AutoHotkey
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()
}
[edit] 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
[edit] 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
[edit] C
int list_cmp(int *a, int la, int *b, int lb)This funciton returns one of three states, not a boolean. One can define boolean comparisons, such as
{
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;
}
list_less_or_eq, based on it:#define list_less_or_eq(a,b,c,d) (list_cmp(a,b,c,d) != 1)
[edit] 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;
}
[edit] clojure
(defn lex? [a b]
(compare a b))
[edit] 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)))))
[edit] 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]);
}
[edit] 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]
[edit] Factor
All sequences respond to words in the math.order vocabulary.
IN: scratchpad { 2 3 } { 2 5 } before? .
t
[edit] Go
package main
import "fmt"
// If your numbers happen to be in the range of Unicode code points (0 to 0x10ffff), this function
// satisfies the task:
func lessRune(a, b []rune) bool {
return string(a) < string(b) // see also bytes.Compare
}
// 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
[edit] 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)
[edit] Haskell
The built-in comparison operators already do this:
Prelude> [1,2,1,3,2] < [1,2,0,4,4,0,0,0]
False
[edit] 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
[edit] J
This is not a built-in in J.
before=: -.@(-: /:~)@,&<~
Example use:
(,0) before ''
0
'' before ''
0
'' before ,0
1
(,_1) before ,0
1
(,0) before ,0
0
(,0) before ,_1
0
(,0) before 0 _1
1
(,0) before 0 0
1
(,0) before 0 1
1
0 _1 before ,0
0
0 0 before ,0
0
0 0 before ,1
1
(,'b') before ''
0
'' before ''
0
'' before ,'b'
1
(,'a') before ,'b'
1
(,'b') before ,'b'
0
(,'b') before ,'a'
0
(,'b') before 'ba'
1
(,'b') before 'bb'
1
(,'b') before 'bc'
1
'ba' before ,'b'
0
'bb' before ,'b'
0
'bb' before ,'c'
1
[edit] Java
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;
}
}
[edit] 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
[edit] LabVIEW
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.
[edit] 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
[edit] Mathematica
order[List1_, List2_] := With[{
L1 = List1[[1 ;; Min @@ Length /@ {List1, List2}]],
L2 = List2[[1 ;; Min @@ Length /@ {List1, List2}]]
},
If [Thread[Order[L1, L2]] == 0,
Length[List1] < Length[List2],
Thread[Order[L1, L2]] == 1
]]
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
[edit] 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
[edit] 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" }.
[edit] OCaml
The built-in comparison operators already do this:
# [1;2;1;3;2] < [1;2;0;4;4;0;0;0];;
- : bool = false
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
[edit] PARI/GP
lex(u,v)<1
[edit] Perl
#!/usr/bin/perl -w
use strict ;
sub orderlists {
my $firstlist = shift ;
my $secondlist = shift ;
my $first = shift @{$firstlist } if @{$firstlist} ;
my $second ;
#keep stripping elements from the first list as long as there are any
#or until the second list is used up!
while ( @{$firstlist} ) {
if ( @{$secondlist} ) { #second list is not used up yet!
$second = shift @{$secondlist} ;
if ( $first < $second ) {
return 1 ;
}
if ( $first > $second ) {
return 0 ;
}
}
else { #second list used up, defined to return false
return 0 ;
}
$first = shift @{$firstlist} ;
}
return 0 ; #in all remaining cases return false
}
my @firstnumbers = ( 43 , 33 , 2 ) ;
my @secondnumbers = ( 45 ) ;
if ( orderlists( \@firstnumbers , \@secondnumbers ) ) {
print "The first list comes before the second list!\n" ;
}
else {
print "The first list does not come before the second list!\n" ;
}
[edit] Perl 6
This 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 = (^100).roll((2..3).pick);
my @b = @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
[edit] 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
[edit] 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;
[edit] 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
Sample output:
False False False True True
[edit] Python
The built-in comparison operators already do this:
>>> [1,2,1,3,2] < [1,2,0,4,4,0,0,0]
False
[edit] 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
[edit] Rascal
The built-in comparison operator already does this:
rascal>[2,1,3] < [5,2,1,3]
bool: true
[edit] REXX
This REXX example uses the same lists as BBC BASIC.
/*REXX pgm finds if list1<list2 (both contain nums), returns true|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
do i=2 while @.i\==''; m=i-1
what=' 'word("< ≥", 1+(FNorder(@.m, @.i)=='false'))" "
say right('['@.m"]", 35) what '['@.i"]"; say
end /*i*/
exit /*stick a fork in it, we're done.*/
/*──────────────────────────────────FNORDER subroutine──────────────────*/
FNorder: procedure; parse arg x,y; wx=words(x); wy=words(y)
do j=1 for min(wx,wy)
if word(x,j)<word(y,j) then return 'true'
end /*j*/
if wx<wy then return 'true'
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]
[edit] Ruby
The built-in <=> operator already does this:
>> ([1,2,1,3,2] <=> [1,2,0,4,4,0,0,0]) < 0
=> false
[edit] 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)))))
[edit] 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
[edit] Standard ML
- List.collate Int.compare ([1,2,1,3,2], [1,2,0,4,4,0,0,0]) = LESS;
val it = false : bool
[edit] Tcl
proc numlist< {A B} {
foreach a $A b $B {
if {$a<$b} {
return 1
} elseif {$a>$b} {
return 0
}
}
return 0
}
[edit] 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
