Order two numerical lists: Difference between revisions

 

Write a function that orders two lists or arrays filled with numbers.

 

<small>Note: further clarification of lexicographical ordering is expounded on the talk page [[Talk:Order_two_numerical_lists#Lexicographic_order|here]] and [[Talk:Order_two_numerical_lists#Is_the_task_statement_consistent.3F|here]].</small>

 

=={{header|ACL2}}==

ACL2 !>(lexorder '(1 2 4) '(1 2 3))

NIL</pre>

 

=={{header|Ada}}==

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

Put_Line (Boolean'Image (List6 > List7)); -- True

end Order;

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<pre>

</pre>

 

 

=={{header|Aime}}==

 

 

=={{header|AppleScript}}==

 

<= is not defined over lists in AppleScript

-- compare :: [a] -> [a] -> Bool

on compare(xs, ys)

missing value

end if

 

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=={{header|AutoHotkey}}==

{{works with|AutoHotkey_L}}

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

List2 := [1,2,0,4,4,0,0,0]

MsgBox % order(List1, List2)

order(L1, L2){

return L1.MaxIndex() < L2.MaxIndex()

 

=={{header|AWK}}==

# syntax: GAWK -f ORDER_TWO_NUMERICAL_LISTS.AWK

BEGIN {

return(ans)

}

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<pre>

list3>=list4

</pre>

 

=={{header|BBC BASIC}}==

'Ordered before' means 'less than' (see [[Talk:Order_two_numerical_lists|talk page]]).

DIM list2(5) : list2() = 1, 2, 1, 5, 2, 2

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

IF list1(i%) < list2(i%) THEN = TRUE

IF list1(i%) > list2(i%) THEN = FALSE

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<pre>

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 1 5 2 2:?List2

& 1 2 1 5 2:?List3

& gt$(!List5,!List6)

& gt$(!List6,!List7)

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<pre>TRUE

 

=={{header|C}}==

{

int i, l = la;

if (la == lb) return 0;

return la > lb ? 1 : -1;

 

=={{header|C sharp|C#}}==

{

using System;

}

}

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<pre>False</pre>

=={{header|C++}}==

The built-in comparison operators already do this:

#include <vector>

 

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

return 0;

 

=={{header|clojure}}==

 

(defn lex? [a b]

(compare a b))

 

=={{header|Common Lisp}}==

(cond ((not b) nil)

((not a) t)

((= (first a) (first b))

(list< (rest a) (rest b)))

 

Alternate version

 

(let ((x (find-if-not #'zerop (mapcar #'- a b))))

 

=={{header|D}}==

The built-in comparison operators already do this:

assert([1,2,1,3,2] >= [1,2,0,4,4,0,0,0]);

 

=={{header|Ela}}==

 

_ <. [] = false

(x::xs) <. (y::ys) | x == y = xs <. ys

| else = x < y

 

 

=={{header|Elixir}}==

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

true

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

 

=={{header|Erlang}}==

Builtin. Example use from Erlang shell:

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

true

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

true

 

=={{header|F_Sharp|F#}}==

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

let before (s1 : seq<'a>) (s2 : seq<'a>) = (Seq.compareWith cmp s1 s2) < 0

 

([0; 0], [1]);

]

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<pre>[0] >= []

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

t

 

=={{header|Go}}==

 

import "fmt"

}

return b

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<pre>

=={{header|Groovy}}==

Solution:

CList() { }

CList(Collection c) { super(c) }

comp ? comp[0] <=> comp[1] : this.size() <=> that.size()

}

 

Test:

b = [1] as CList; assert (a < b)

a = [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)

 

=={{header|Haskell}}==

The built-in comparison operators already do this:

 

=={{header|Icon}} and {{header|Unicon}}==

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

 

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

end

else if L1[i] >> L2[i] then fail

if *L1 < *L2 then return L2

 

=={{header|J}}==

 

 

 

 

 

=={{header|Java}}==

{{trans|Common Lisp}}

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

import java.util.List;

 

return i == first.length;

}

 

=={{header|JavaScript}}==

<= is already defined for numeric lists in JavaScript

 

'use strict';

 

// --> [false, true]

})()

 

{{Out}}

 

=={{header|Joy}}==

DEFINE order ==

[equal] [false]

[[[[size] dip size <=] [[<=] mapr2 true [and] fold]] [i] map i and]

ifte.

 

Using it:

 

=={{header|jq}}==

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

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

 

=={{header|Julia}}==

{{works with|Julia|0.6}}

 

for (x, y) in zip(a, b)

if x == y continue end

println("List not sorted:\n - ", join(tests, "\n - "))

sort!(tests; lt=islexless)

 

{{out}}

- [3.14159, 2.71828, 1.61803, 0.915966]

- [2015, 5]</pre>

 

=={{header|Kotlin}}==

 

operator fun <T> List<T>.compareTo(other: List<T>): Int

println()

for (i in 0 until lists.size - 1) println("list${i + 1} > list${i + 2} = ${lists[i] > lists[i + 1]}")

 

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=={{header|Lasso}}==

This is built into the Lasso comparison operators

first = array(1,2,1,3,2),

second = array(1,2,0,4,4,0,0,0),

second = array(1,2,0,4,4,0,0,0),

)

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<pre>false

Uses standard '=' notation

 

print [1 2] = [1 2 3]

print [1 3] = [1 2]

make "list1 [1 2 3 4 5 6]

make "list2 [1 2 3 4 5 7]

 

{{out}}

false

false

false

 

=={{header|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:

for i = 1, #a do

if b[i] == nil then

end

return true

 

Here is some demonstration code:

 

local t = {}

for i = 1, math.random(1, 10) do

arraycompare(a, b) and "<=" or ">",

table.concat(b, ', ')))

 

{{out}} (time used as random seed: 1413127434):

</pre>

 

L1 = List1[[1 ;; Min @@ Length /@ {List1, List2}]],

L2 = List2[[1 ;; Min @@ Length /@ {List1, List2}]]

Length[List1] < Length[List2],

Thread[Order[L1, L2]] == 1

 

<pre>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</pre>

 

=={{header|Maxima}}==

catch(for i thru n do (if a[i]#b[i] then throw(is(a[i]<b[i]))),

throw(is(length(a)<length(b)))))$

 

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

 

=={{header|Mercury}}==

For a particular numerical type, you can get away with

 

lt([], [_|_]).

 

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

 

lt([], [_|_]).

 

... which you would have to create:

 

:- interface.

:- import_module int, float, integer, list.

 

% pred lt

 

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

 

:- 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,

 

=={{header|Nim}}==

for i in 0 .. min(a.len, b.len):

if a[i] < b[i]: return true

return a.len < b.len

 

{{out}}

<pre>false</pre>

 

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

 

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

)

 

But we could write it explicitly this way:

 

| x1::tl1, x2::tl2 ->

(match compare x1 x2 with

| _ -> true)

| [], _ -> true

 

Here is a small script to test this function:

 

 

let make_num_list p n =

print_num_list lst1;

print_num_list lst2;

 

Sample execution:

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

 

 

=={{header|Oforth}}==

1 ok

</pre>

 

=={{header|PARI/GP}}==

 

=={{header|Perl}}==

use warnings;

 

my $before = orderlists([@$first], [@$second]) ? 'true' : 'false';

print "(@$first) comes before (@$second) : $before\n";

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<pre>

</pre>

 

 

 

 

 

 

=={{header|PicoLisp}}==

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

 

=={{header|Pike}}==

{

if (!sizeof(a)) return true;

return order_array(a[1..], b[1..]);

return a[0] < b[0];

Pikes <code>Array.sort_array()</code> function can sort an array of arrays using the <code><</code> 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:

 

=={{header|PL/I}}==

 

declare a(10) fixed initial (1, 2, 3, 4, 5, 8, 9, 10, 16, 17),

end compare;

 

Results:

<pre>

 

=={{header|PowerShell}}==

function order($as,$bs) {

if($as -and $bs) {

}

"$(order @(1,2,1,3,2) @(1,2,0,4,4,0,0,0))"

<b>Output:</b>

<pre>

 

===Non-Recursive Version===

function Test-Order ([int[]]$ReferenceArray, [int[]]$DifferenceArray)

{

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 -DifferenceArray 1, 2, 3

Test-Order -ReferenceArray 1, 2 -DifferenceArray 1, 2

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<pre>

 

=={{header|PureBasic}}==

Array_1:

Data.i 5 ;element count

CloseConsole()

EndIf

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<pre>False

=={{header|Python}}==

The built-in comparison operators already do this:

 

=={{header|Racket}}==

 

(define (lex<? a b)

 

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

 

=={{header|Rascal}}==

The built-in comparison operator already does this:

 

=={{header|REXX}}==

 

<pre>

[1 2 1 5 2] < [1 2 1 5 2 2]

 

=={{header|Ring}}==

list1 = "1, 2, 1, 5, 2"

list2 = "5, 2, 1, 5, 2, 2"

func order alist, blist

return strcmp(alist, blist)

Output:

<pre>

list2>list3

list3=list4

</pre>

 

=={{header|Ruby}}==

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

 

=={{header|Scala}}==

if (b.isEmpty) false

else if (a.isEmpty) true

else if (a.head != b.head) a.head < b.head

case (_, Nil) => false

case (Nil, _) => true

case (a :: _, b :: _) if a != b => a < b

case _ => lessThan2(a.tail, b.tail)

a.zipAll(b, Integer.MIN_VALUE, Integer.MIN_VALUE)

.find{case (a, b) => a != b}

.map{case (a, b) => a < b}

(List(1, 2, 3), List(1, 2, 3)) -> false,

(List(3, 2, 1), List(3, 2, 1)) -> false,

assert(lessThan2(a, b) == c, test)

assert(lessThan3(a, b) == c, test)

 

=={{header|Scheme}}==

(cond ((null? b) #f)

((null? a) #t)

((= (car a) (car b)) (lex<? (cdr a) (cdr b)))

 

=={{header|Seed7}}==

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

 

 

const proc: main is func

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

 

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=={{header|Sidef}}==

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

(a <=> b) < 0

}

var before = ordered(a, b)

say "#{a} comes before #{b} : #{before}"

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<pre>

 

=={{header|Standard ML}}==

 

=={{header|Swift}}==

let b = [1,2,0,4,4,0,0,0]

{{out}}

<pre>

 

=={{header|Tcl}}==

foreach a $A b $B {

if {$a<$b} {

}

return 0

 

=={{header|TUSCRIPT}}==

$$ MODE TUSCRIPT

MODE DATA

list1=VALUE(list2)

ENDLOOP

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<pre style='height:30ex;overflow:scroll'>

true: 1'2 < 1'2'4

</pre>

 

=={{header|VBScript}}==

Function order_list(arr1,arr2)

order_list = "FAIL"

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))

 

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=={{header|Wart}}==

We'll simply overload <code>&lt;</code> for lists.

if not.b

nil

(cdr.a < cdr.b)

:else

 

{{out}}

(< '(1 2 4) '(1 2 3 4))

=> nil</pre>

 

=={{header|zkl}}==

a.walker().zip(b).filter1(fcn([(a,b)]){ a<b }) : // lazy

if(_) return(True);;

a.len()<b.len()

{{out}}

<pre>