PHP - Check if two arrays are equal

Question

I'd like to check if two arrays are equal. I mean: same size, same index, same values. How can I do that?

Using !== as suggested by a user, I expect that the following would print enter if at least one element in the array(s) are different, but in fact it does not.

if (($_POST['atlOriginal'] !== $oldAtlPosition) 
    or ($_POST['atl'] !== $aext) 
    or ($_POST['sidesOriginal'] !== $oldSidePosition) 
    or ($_POST['sidesOriginal'] !== $sideext)) {

    echo "enter";
}

Answer 1

$arraysAreEqual = ($a == $b); // TRUE if $a and $b have the same key/value pairs.
$arraysAreEqual = ($a === $b); // TRUE if $a and $b have the same key/value pairs in the same order and of the same types.

See Array Operators.

EDIT

The inequality operator is != while the non-identity operator is !== to match the equality operator == and the identity operator ===.

Answer 2

According to this page.

NOTE: The accepted answer works for associative arrays, but it will not work as expected with indexed arrays (explained below). If you want to compare either of them, then use this solution. Also, this function may not works with multidimensional arrays (due to the nature of array_diff function).

Testing two indexed arrays, which elements are in different order, using $a == $b or $a === $b fails, for example:

<?php
    (array("x","y") == array("y","x")) === false;
?>

That is because the above means:

array(0 => "x", 1 => "y") vs. array(0 => "y", 1 => "x").

To solve that issue, use:

<?php
function array_equal($a, $b) {
    return (
         is_array($a) 
         && is_array($b) 
         && count($a) == count($b) 
         && array_diff($a, $b) === array_diff($b, $a)
    );
}
?>

Comparing array sizes was added (suggested by super_ton) as it may improve speed.

Answer 3

Try serialize. This will check nested subarrays as well.

$foo =serialize($array_foo);
$bar =serialize($array_bar);
if ($foo == $bar) echo "Foo and bar are equal";

Answer 4

Short solution that works even with arrays which keys are given in different order:

public static function arrays_are_equal($array1, $array2)
{
    array_multisort($array1);
    array_multisort($array2);
    return ( serialize($array1) === serialize($array2) );
}

Answer 5

function compareIsEqualArray(array $array1,array $array2):bool
{

   return (array_diff($array1,$array2)==[] && array_diff($array2,$array1)==[]);

}

Answer 6

Compare them as other values:

if($array_a == $array_b) {
  //they are the same
}

You can read about all array operators here: http://php.net/manual/en/language.operators.array.php Note for example that === also checks that the types and order of the elements in the arrays are the same.

Answer 7

if (array_diff($a,$b) == array_diff($b,$a)) {
  // Equals
}

if (array_diff($a,$b) != array_diff($b,$a)) {
  // Not Equals
}

From my pov it's better to use array_diff than array_intersect because with checks of this nature the differences returned commonly are less than the similarities, this way the bool conversion is less memory hungry.

Edit Note that this solution is for plain arrays and complements the == and === one posted above that is only valid for dictionaries.

Answer 8

Another method for checking equality regardless of value order works by using 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';
}

Here's a version that works also with multidimensional arrays using http://php.net/manual/en/function.array-uintersect.php:

$array1 = array(
    array(5, 2),
    array(3, 6),
    array(2, 9, 4)
);
$array2 = array(
    array(3, 6),
    array(2, 9, 4),
    array(5, 2)
);

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

function compare($v1, $v2) {
    if ($v1===$v2) {
        return 0;
    }
    if ($v1 > $v2) return 1;
    return -1;
}

Answer 9

One way: (implementing 'considered equal' for https://www.rfc-editor.org/rfc/rfc6902#section-4.6)

This way allows associative arrays whose members are ordered differently - e.g. they'd be considered equal in every language but php :)

// recursive ksort
function rksort($a) {
  if (!is_array($a)) {
    return $a;
  }
  foreach (array_keys($a) as $key) {
    $a[$key] = ksort($a[$key]);
  }
  // SORT_STRING seems required, as otherwise
  // numeric indices (e.g. "0") aren't sorted.
  ksort($a, SORT_STRING);
  return $a;
}


// Per https://www.rfc-editor.org/rfc/rfc6902#section-4.6
function considered_equal($a1, $a2) {
  return json_encode(rksort($a1)) === json_encode(rksort($a2));
}

Answer 10

Syntax problem on your arrays

$array1 = array(
    'a' => 'value1',
    'b' => 'value2',
    'c' => 'value3',
 );

$array2 = array(
    'a' => 'value1',
    'b' => 'value2',
    'c' => 'value3',
 );

$diff = array_diff($array1, $array2);

var_dump($diff); 

Answer 11

array_diff — Computes the difference of arrays

http://php.net/manual/en/function.array-diff.php

array array_diff ( array $array1 , array $array2 [, array $... ] )

Compares array1 against one or more other arrays and returns the values in array1 that are not present in any of the other arrays.

Answer 12

Here is the example how to compare to arrays and get what is different between them.

$array1 = ['1' => 'XXX', 'second' => [
            'a' => ['test' => '2'],
            'b' => 'test'
        ], 'b' => ['no test']];

        $array2 = [
            '1' => 'XX',
            'second' => [
                'a' => ['test' => '5', 'z' => 5],
                'b' => 'test'
            ],
            'test'
        ];


        function compareArrayValues($arrayOne, $arrayTwo, &$diff = [], $reversed = false)
        {
            foreach ($arrayOne as $key => $val) {
                if (!isset($arrayTwo[$key])) {
                    $diff[$key] = 'MISSING IN ' . ($reversed ? 'FIRST' : 'SECOND');
                } else if (is_array($val) && (json_encode($arrayOne[$key]) !== json_encode($arrayTwo[$key]))) {
                    compareArrayValues($arrayOne[$key], $arrayTwo[$key], $diff[$key], $reversed);
                } else if ($arrayOne[$key] !== $arrayTwo[$key]) {
                    $diff[$key] = 'DIFFERENT';
                }
            }
        }

        $diff = [];
        $diffSecond = [];

        compareArrayValues($array1, $array2, $diff);
        compareArrayValues($array2, $array1, $diffSecond, true);

        print_r($diff);
        print_r($diffSecond);

        print_r(array_merge($diff, $diffSecond));

Result:

Array
(
    [0] => DIFFERENT
    [second] => Array
        (
            [a] => Array
                (
                    [test] => DIFFERENT
                    [z] => MISSING IN FIRST
                )

        )

    [b] => MISSING IN SECOND
    [1] => DIFFERENT
    [2] => MISSING IN FIRST
)

Answer 13

Given:

$array1 = ['a', 'b', '3'];
$array2 = ['a', 'b', '3'];

$array1 == $array2  //true
$array1 === $array2 //true

Given:

$array1 = ['a', 'b', 3];
$array2 = ['a', 'b', '3'];

$array1 == $array2  //true
$array1 === $array2 //false

Given:

$array1 = ['3', 'a', 'b'];
$array2 = ['a', 'b', '3'];

$array1 == $array2  //false
$array1 === $array2 //false

The solution, sort in same order

$array1 = ['3', 'a', 'b'];
$array2 = ['a', 'b', '3'];

sort($array1);
sort($array2);

$array1 == $array2  //true
$array1 === $array2 //true

Answer 14

If you want to check non associative arrays, here is the solution:

$a = ['blog', 'company'];
$b = ['company', 'blog'];

(count(array_unique(array_merge($a, $b))) === count($a)) ? 'Equals' : 'Not Equals';
// Equals

Answer 15

The following solution works with custom equality functions that you can pass as a callback. Note that it doesn't check arrays order.

trait AssertTrait
{
    /**
     * Determine if two arrays have the same elements, possibly in different orders. Elements comparison function must be passed as argument.
     *
     * @param array<mixed> $expected
     * @param array<mixed> $actual
     *
     * @throws InvalidArgumentException
     */
    public static function assertArraysContainSameElements(array $expected, array $actual, callable $comparisonFunction): void
    {
        Assert::assertEquals(\count($expected), \count($actual));

        self::assertEveryElementOfArrayIsInAnotherArrayTheSameAmountOfTimes($expected, $actual, $comparisonFunction);
        self::assertEveryElementOfArrayIsInAnotherArrayTheSameAmountOfTimes($actual, $expected, $comparisonFunction);
    }

    /**
     * @param array<mixed> $needles
     * @param array<mixed> $haystack
     *
     * @throws InvalidArgumentException
     */
    private static function assertEveryElementOfArrayIsInAnotherArrayTheSameAmountOfTimes(
        array $needles,
        array $haystack,
        callable $comparisonFunction
    ): void {
        Assert::assertLessThanOrEqual(\count($needles), \count($haystack));

        foreach ($needles as $expectedElement) {
            $matchesOfExpectedElementInExpected = \array_filter(
                $needles,
                static fn($element): bool => $comparisonFunction($expectedElement, $element),
            );

            $matchesOfExpectedElementInActual = \array_filter(
                $haystack,
                static fn($element): bool => $comparisonFunction($expectedElement, $element),
            );

            Assert::assertEquals(\count($matchesOfExpectedElementInExpected), \count($matchesOfExpectedElementInActual));
        }
    }
}

I usually use it in database integrations tests when I want to ensure that the expected elements are returned but I don't care about the sorting.

Answer 16

The proper way to compare whether two arrays are equal is to use strict equality (===), which compares recursively. Existing answers are unable to recursively sort an arbitrary array (array of arbitrary depth and order, containing a mixture of sequential and associative arrays) and hence cannot handle comparisons of arbitrary arrays. Sequential arrays are associative arrays with a sequential key (0,1,2,3...) whereas associative arrays do not have a sequential key.

To sort these arbitrary arrays, we have to:

1. Traverse downwards towards leaf nodes with no more sub-arrays
2. Sort sequential arrays by serializing then sorting them (to remove the need of having to use custom comparators)
3. Sort associative arrays by key

The following code implements the solution described above. Improvements to the code are welcome.

function recur_sort( &$array ) {
    foreach ( $array as &$value ) {
       if ( is_array( $value ) ) recur_sort( $value );
    }

    if ( is_sequential_array( $array ) ) {
        $array = array_map( function( $el ) { return json_encode( $el ); }, $array  );
        sort( $array, SORT_STRING );
        $array = array_map( function( $el ) { return json_decode( $el, true ); }, $array  );
        return;
    } else {
        return ksort( $array );
    }
}

function is_sequential_array(Array &$a) {
    $n = count($a);
    for($i=0; $i<$n; $i++) {
        if(!array_key_exists($i, $a)) {
            return false;
        }
    }
    return true;
}

Example (in PHPUnit):

//A stricter and recursive assertEqualsCanonicalizing
public function assertSameCanonicalizing( $expected, $actual ) {
    recur_sort( $expected );
    recur_sort( $actual );
    $this->assertSame( $expected, $actual );
}

Answer 17

If you want to check that your arrays have the strictly equal (===) associations of keys and values, you can use the following function:

function array_eq($a, $b) {
    // If the objects are not arrays or differ in their size, they cannot be equal
    if (!is_array($a) || !is_array($b) || count($a) !== count($b)) {
        return false;
    }
    // If the arrays of keys are not strictly equal (after sorting),
    // the original arrays are not strictly equal either
    $a_keys = array_keys($a);
    $b_keys = array_keys($b);
    array_multisort($a_keys);
    array_multisort($b_keys);
    if ($a_keys !== $b_keys) {
        return false;
    }
    // Comparing values
    foreach ($a_keys as $key) {
        $a_value = $a[$key];
        $b_value = $b[$key];
        // Either the objects are strictly equal or they are arrays
        // which are equal according to our definition. Otherwise they
        // are different.
        if ($a_value !== $b_value && !array_eq($a_value, $b_value)) {
            return false;
        }
    }
    return true;
}

Answer 18

To compare the values of your arrays, also multidimensional, associative and in any combination:

/**
 * @see PHPUnit Assert::assertEqualsCanonicalizing()
 * @return true if all keys and values are equal and of the same type,
 * irregardless of items or keys order
 */
function array_vals_equal(array $a, array $b): bool {
    // sort multi-dimensional recursive
    $_deep_sort = function (array $a) use (&$_deep_sort): array{
        // sort discarding index association or sort keys, depending on array type
        array_is_list($a) ? sort($a) : ksort($a);
        return array_map(fn($v) => is_array($v) ? $_deep_sort($v) : $v, $a);
    };
    // operator === checks that the count, types and order of the elements are the same
    return $_deep_sort($a) === $_deep_sort($b);
}

// Test cases
assertEquals(array_vals_equal([1], [1]), true, 'simple eq');
assertEquals(array_vals_equal([0], [false]), false, 'simple eq');
assertEquals(array_vals_equal([0], [null]), false, 'simple eq');
assertEquals(array_vals_equal([0, 1], [1, 0]), true, 'simple eq, diff order');
assertEquals(array_vals_equal([0, 1, 2], [1, 0]), false, 'diff count');
assertEquals(array_vals_equal([0, 1], [0, 1, 2]), false, 'diff count 2');
assertEquals(array_vals_equal([1, 2], [1, 2, 'hello']), false, 'diff count 3');
//
assertEquals(array_vals_equal([1, 2, 2], [2, 1, 1]), false, 'same vals repeated');
assertEquals(array_vals_equal([1, 2, 2], [2, 2, 1]), true, 'same vals, different order');
//
assertEquals(array_vals_equal([1, 2, 3], ['1', '2', '3']), false, 'int should not be eq string');
assertEquals(array_vals_equal([0 => 'a', 1 => 'b'], [0 => 'b', 1 => 'a']), true, 'same vals, diff order');
assertEquals(array_vals_equal(['a', 'b'], [3 => 'b', 5 => 'a']), true, 'same vals, diff indexes');
// associative arrays whose members are ordered differently
assertEquals(array_vals_equal(['aa' => 'a', 'bb' => 'b'], ['bb' => 'b', 'aa' => 'a']), true, 'dict with different order');
assertEquals(array_vals_equal(['aa' => 'a', 'bb' => 'b'], ['aa' => 'a']), false, 'a key is missing');
assertEquals(array_vals_equal(['aa' => 'a', 'bb' => 'b'], ['aa' => 'a', 'zz' => 'b']), false, 'dict same vals diff key');
// nested arrays with keys in different order
assertEquals(array_vals_equal(
    ['aa' => 'a', 'bb' => ['bb' => 'b', 'aa' => 'a']],
    ['aa' => 'a', 'bb' => ['aa' => 'a', 'bb' => 'b']]
), true, 'dict multi 2 level, keys in different order');
assertEquals(array_vals_equal(
    ['aa' => 'a', 'bb' => ['aa2' => 'a', 'bb2' => ['aa3' => 'a', 'bb3' => 'b']]],
    ['aa' => 'a', 'bb' => ['aa2' => 'a', 'bb2' => ['aa3' => 'a', 'bb3' => 'b']]]
), true, 'dict multi 3 level');
assertEquals(array_vals_equal(
    ['aa' => 'a', 'bb' => [0, 1]],
    ['aa' => 'a', 'bb' => [1, 0]]
), true, 'dict multi level, 2^ level sequential in different order');
assertEquals(array_vals_equal([[0, 1], ['a', 'b']], [['b', 'a'], [1, 0]]), true, 'multi level sequential');

Answer 19

If you'd like to generate a detailed report, you could use something like this:

function deepCompare(Array $a, Array $b, string $parentAKey, string $parentBKey, bool $compareInverted = true, bool $compareValues = true, string $log = '')
{
    foreach ($a as $aKey => $aValue) {
        $fullAKey = implode('.', [$parentAKey, $aKey]);
        $fullBKey = implode('.', [$parentBKey, $aKey]);
        if (! isset($b[$aKey])) {
            $log .= "⍰ {$fullAKey} has no equivalent {$fullBKey}\n";
        } else {
            $bValue = $b[$aKey];
            if (is_array($aValue)) {
                $log = deepCompare($aValue, $bValue, $fullAKey, $fullBKey, false, $compareValues, $log);
            } else {
              if ($compareValues) {
                  if ($aValue != $bValue) {
                      $log .= "≠ {$fullAKey} value differs from {$fullBKey}\n";
                  }
              }
            }
        }
    }
    if ($compareInverted) {
        $log = deepCompare($b, $a, $parentBKey, $parentAKey, false, false, $log);
    }
    return $log;
}

Here is an example for it:

$november = [
  'site1' => [
    'id' => 15,
    'name' => 'Brazil',
    'extendedHours' => 454,
  ],
  'site2' => [
    'id' => 43,
    'name' => 'Portugal',
    'extendedHours' => 448,
  ],
  'site3' => [
    'id' => 49,
    'name' => 'Spain',
    'extendedHours' => 0,
  ],  
  'totalExtendedHours' => 902,
];

$december = [
  'site1' => [
    'id' => 15,
    'name' => 'Brazil',
    'extendedHours' => 498,
  ],
  'site2' => [
    'id' => 43,
    'name' => 'Portugal',
    'extendedHours' => 409,
    'extraRequests' => 6,
  ],
  'totalExtendedHours' => 907,
  'totalExtraRequests' => 6,
];

echo deepCompare(
    $november,    -- origin array
    $december,    -- target array
    'Nov2022',    -- descriptive name of origin array
    'Dec2022',    -- descriptive name of target array
    true,         -- should also compare arrays in reverse order?
    true          -- should care about array values? (false = names only)
);

This example will output:

≠ Nov2022.site1.extendedHours value differs from Dec2022.site1.extendedHours
≠ Nov2022.site2.extendedHours value differs from Dec2022.site2.extendedHours
⍰ Nov2022.site3 has no equivalent Dec2022.site3
≠ Nov2022.totalExtendedHours value differs from Dec2022.totalExtendedHours
⍰ Dec2022.site2.extraRequests has no equivalent Nov2022.site2.extraRequests
⍰ Dec2022.totalExtraRequests has no equivalent Nov2022.totalExtraRequests

I hope that helps someone.

Answer 20

Use php function array_diff(array1, array2);

It will return a the difference between arrays. If its empty then they're equal.

example:

$array1 = array(
    'a' => 'value1',

    'b' => 'value2',

    'c' => 'value3'
 );

$array2 = array(
    'a' => 'value1',

    'b' => 'value2',

    'c' => 'value4'
 );

$diff = array_diff(array1, array2);

var_dump($diff); 

//it will print array = (0 => ['c'] => 'value4' ) 

Example 2:

$array1 = array(
    'a' => 'value1',

    'b' => 'value2',

    'c' => 'value3',
 );

$array2 = array(
    'a' => 'value1',

    'b' => 'value2',

    'c' => 'value3',
 );

$diff = array_diff(array1, array2);

var_dump($diff); 

//it will print empty;