How to check if two indexed arrays have same values even if the order is not same? [duplicate]

Question

I want to compare two indexed arrays as such that values will be same for two arrays but order may differ, for example i tried doing this but it simply doesn't work.

Example 1 :

$a = array(1,2,3,4,5);
$b = array(1,2,3,5,4);
echo ($a == $b) ? 'Match Found' : 'No Match Found';
//Returns No Match Found

Example 2 : (tried sorting the array but it doesn't sort)

$a = array(1,2,3,4,5);
$a = sort($a);
$b = array(1,2,3,5,4);
$b = sort($b);
echo ($a === $b) ? 'Match Found' : 'No Match Found';
//Returns Match Found

above example returns match Found and that is because sort() returns 1 if i try sorting indexed array, and both $a and $b contains 1 after sorting resulting in condition being true which is totally wrong, this trick does not seems to work either, i tried with many different sorting function like asort(), arsort() etc, but none seems to work.

what is the workaround for this?

thank you

The canonical on not using sort()'s returned value: Sorting the array from an exploded string returns true instead of the sorted array loads of dupes. — mickmackusa
– mickmackusa ♦, Commented Feb 4 at 9:48

Andrew Winter · Accepted Answer · 2011-07-30 04:37:25Z

4

$a = array(1,2,3,4,5);
$b = array(1,3,2,5,3,4);


if(count($a) == count($b) && count(array_diff($a, $b)) == 0){
    echo "A";
}

Need to do a length check or the two arrays above would come out the same.

edit: better solution.

edited Jul 30, 2011 at 4:37

answered Jul 30, 2011 at 4:26

Andrew Winter

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Comments

Explosion Pills · Accepted Answer · 2011-07-30 04:24:41Z

1

Instead of comparing the return values of sort, why don't you just compare the arrays after they have been sorted?

$a = array(1,2,3,4,5);
sort($a);
$b = array(1,2,3,5,4);
sort($b);
echo ($a == $b) ? 'Match Found' : 'No Match Found';

If the arrays have different keys but the same values, they will still count as equal. You must also compare the array keys if this is an issue.

answered Jul 30, 2011 at 4:24

Explosion Pills

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Comments

Aymen Turki · Accepted Answer · 2025-02-04 09:44:41Z

This answer would unexpectedly display "Match Found", in this use case:

$a = array(5,1,2,"3",4);
sort($a);
$b = array(1,3,5,"4","2");
sort($b);
echo ($a == $b) ? 'Match Found' : 'No Match Found'; // displays "Match Found"

And this wouldn't (just added the "aa" element to the two arrays):

$a = array(5,1,2,"3",4,"aa");
sort($a);
var_dump($a);
$b = array(1,3,5,"4","2","aa");
sort($b);
var_dump($b); // not same ordering
echo ($a == $b) ? 'Match Found' : 'No Match Found'; // displays "No Match Found"

Better compare apples to apples; convert the two arrays to arrays of strings:

$a = array(5,1,2,"3",4,"aa");
$a = array_map("strval", $a); // conversion to an array of strings
sort($a);
$b = array(1,3,5,"4","2","aa");
$b = array_map("strval", $b); // conversion to an array of strings
sort($b);

echo ($a == $b) ? 'Match Found' : 'No Match Found'; // displays "Match Found"

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