Check if two arrays have the same values

Question

[2,5,3]    

[5,2,3]

They are equal because they have the same values, but not in the same order. Can I find out that without using a foreach loop with in_array() ? I dont think it would be efficient.

Answer 1

sort($a);
sort($b);
if ($a===$b) {//equal}

Answer 2

Coming to this party late. I had the same question but didn't want to sort, which was the immediate answer I knew would work. I came up with this simple one-liner which only works for arrays of unique values:

$same = ( count( $a ) == count( $b ) && !array_diff( $a, $b ) )

It's also about a factor of 5 faster than the sort option. Not that either is especially slow, so I would say it is more about your personal preferences and which one you think is more clear. Personally I would rather not sort.

Edit: Thanks Ray for pointing out the fact that this only works with arrays with unique values.

Answer 3

This is a bit late to the party but in hopes that it will be useful:

If you are sure the arrays both only contain strings or both only contain integers, then array_count_values($a) == array_count_values($b) has better time complexity. However, user1844933's answer is more general.

Answer 4

If you don't want to sort arrays but just want to check equality regardless of value order use http://php.net/manual/en/function.array-intersect.php like so:

$array1 = array(2,5,3);
$array2 = array(5,2,3);
if($array1 === array_intersect($array1, $array2) && $array2 === array_intersect($array2, $array1)) {
    echo 'Equal';
} else {
    echo 'Not equal';
}

Answer 5

The best way will be using array_diff http://php.net/manual/en/function.array-diff.php

$arr1 = [2,5,3];
$arr2 = [5,2,3];

$isEqual = array_diff($arr1,$arr2) === array_diff($arr2,$arr1);

Answer 6

As none of the given answers that are completely key-independent work with duplicated values (like [1,1,2] equals [1,2,2]) I've written my own.

This variant does not work with multi-dimensional arrays. It does check whether two arrays contain the exactly same values, regardless of their keys and order without modifying any of the arguments.

function array_equals(array $either, array $other) : bool {
    foreach ($other as $element) {
        $key = array_search($element, $either, true);
        if ($key === false) {
            return false;
        }
        unset($either[$key]);
    }
    return empty($either);
}

Although the question asked about a foreach-free variant, I couldn't find any solution that satisfied my requirements without a loop. Additionally most of the otherwise used functions use a loop internally too.

---

Why does it not modify $either? Because values in PHP are copy-on-write, so as long as this is its own function and not inline code the array is copied once the $either argument is modified for the first time.

If you want to inline this code do this before:

$either = $myarray;
// inline code from function above

Answer 7

Say, if you have two arrays defined like this:

$array1 = array(2,5,3);
$array2 = array(5,2,3);

Then you can use this piece of code to judge whether they equal:

if(array_diff($array1,$array2) === array_diff($array2,$array1) &&count($array1)==count($array2))
{
    echo 'Equal';
}
else
{
    echo 'Not equal';
}

Answer 8

How about converting the arrays to strings and then comparing the strings.

sort($a);
sort($b);
$a_str = implode(",", $a);
$b_str = implode(",", $b);
f ( strcmp($a_str, $b_str) !== 0)
{
}

Answer 9

function array_equal($a, $b){
return count($a) === count($b) && empty(array_diff($a, $b)) && empty(array_diff($b, $a));
}

Here is the accurate solution

Answer 10

I came across this problem and solve it thus: I needed to ensure that two objects had the same fields So

const expectedFields = ['auth', 'message'];
const receivedFields = Object.keys(data);
const everyItemexists = expectedFields.map(i => receivedFields.indexOf(i) > -1);
const condition = everyItemexists.reduce((accumulator, item) => item && accumulator, true);

Basically, go through one of the arrays, here (I'm assuming there are of the same size though). Then check if its exists in the other array. Then i reduce the result of that.

Answer 11

$array1 = array(2,5,3);
$array2 = array(5,2,3);
$result = array_diff($array1, $array2);
if(empty($result))
{
   echo "Both arrays are equal.";
}
else
{
   echo "Both arrays are different.";
}