array_diff_assoc

    (PHP 4 >= 4.3.0, PHP 5, PHP 7, PHP 8)

    array_diff_assoc — Computes the difference of arrays with additional index check

    Description

    array_diff_assoc(array $array, array ...$arrays): array

    Compares array against arrays and returns the difference. Unlike array_diff() the array keys are also used in the comparison.

    Parameters

    array

    The array to compare from

    arrays

    Arrays to compare against

    Return Values

    Returns an array containing all the values from array that are not present in any of the other arrays.

    Changelog

    Version Description
    8.0.0 This function can now be called with only one parameter. Formerly, at least two parameters have been required.

    Examples

    Example #1 array_diff_assoc() example

    In this example the "a" => "green" pair is present in both arrays and thus it is not in the output from the function. Unlike this, the pair 0 => "red" is in the output because the key of "red" is automatically assigned to 0 in the first array, whereas it is assigned to 1 in the second array as the key 0 is already taken by yellow.

    <?php
    $array1     = array("a" => "green", "b" => "brown", "c" => "blue", "red");
    $array2 = array("a" => "green", "yellow", "red");
    $result = array_diff_assoc($array1, $array2);
    print_r($result);
    ?>

    The above example will output:

    Array
(
    [b] => brown
    [c] => blue
    [0] => red
)

    Example #2 array_diff_assoc() example

    Two values from key => value pairs are considered equal only if (string) $elem1 === (string) $elem2 . In other words a strict check takes place so the string representations must be the same.

    <?php
    $array1     = array(0, 1, 2);
    $array2 = array("00", "01", "2");
    $result = array_diff_assoc($array1, $array2);
    print_r($result);
    ?>

    The above example will output:

    Array
(
    [0] => 0
    [1] => 1
)

    Notes

    Note: This function only checks one dimension of an n-dimensional array. It is possible to check deeper dimensions by using, for example, array_diff_assoc($array1[0], $array2[0]);.

    Note: Ensure arguments are passed in the correct order when comparing similar arrays with more keys. The new array should be the first in the list.

    See Also

    • array_diff() - Computes the difference of arrays
    • array_diff_uassoc() - Computes the difference of arrays with additional index check which is performed by a user supplied callback function
    • array_udiff_assoc() - Computes the difference of arrays with additional index check, compares data by a callback function
    • array_udiff_uassoc() - Computes the difference of arrays with additional index check, compares data and indexes by a callback function
    • array_intersect() - Computes the intersection of arrays
    • array_intersect_assoc() - Computes the intersection of arrays with additional index check

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    User Contributed Notes 21 notes

    up
    62
    Giosh
    11 years ago
    The array_diff_assoc_array from "chinello at gmail dot com" (and others) will not work for arrays with null values. That's because !isset is true when an array key doesn't exists or is set to null.

    (sorry for the changed indent-style)
    <?php
    function array_diff_assoc_recursive($array1, $array2) {
    $difference=array();
    foreach(    $array1 as $key => $value) {
    if(     is_array($value) ) {
    if( !isset(    $array2[$key]) || !is_array($array2[$key]) ) {
    $difference[$key] = $value;
    } else {
    $new_diff = array_diff_assoc_recursive($value, $array2[$key]);
    if( !empty(    $new_diff) )
    $difference[$key] = $new_diff;
    }
    } else if( !    array_key_exists($key,$array2) || $array2[$key] !== $value ) {
    $difference[$key] = $value;
    }
    }
    return     $difference;
    }
    ?>

    And here an example (note index 'b' in the output):
    <?php
    $a1    =array( 'a' => 0, 'b' => null, 'c' => array( 'd' => null ) );
    $a2=array( 'a' => 0, 'b' => null );

    var_dump( array_diff_assoc_recursive( $a1, $a2 ) );
    var_dump( chinello_array_diff_assoc_recursive( $a1, $a2 ) );
    ?>
    array(1) {
    ["c"]=>
    array(1) {
    ["d"]=>
    NULL
    }
    }

    array(2) {
    ["b"]=>
    NULL
    ["c"]=>
    array(1) {
    ["d"]=>
    NULL
    }
    }
    up
    13
    contact at pascalopitz dot com
    17 years ago
    The direction of the arguments does actually make a difference:

    <?php
    $a     = array(
    'x' => 'x',
    'y' => 'y',
    'z' => 'z',
    't' => 't',
    );

    $b = array(
    'x' => 'x',
    'y' => 'y',
    'z' => 'z',
    't' => 't',
    'g' => 'g',
    );

    print_r(array_diff_assoc($a, $b));
    print_r(array_diff_assoc($b, $a));
    ?>

    echoes:

    Array
    (
    )
    Array
    (
    [g] => g
    )
    up
    5
    telefoontoestel at hotmail dot com
    10 years ago
    an earlier post for recursive array_diff_assoc failed because isset returned false on an array element containing a null value. I updated the code so it compares null values too.

    <?php
    function array_diff_assoc_recursive($array1, $array2)
    {
    foreach(    $array1 as $key => $value)
    {
    if(    is_array($value))
    {
    if(!isset(    $array2[$key]))
    {
    $difference[$key] = $value;
    }
    elseif(!    is_array($array2[$key]))
    {
    $difference[$key] = $value;
    }
    else
    {
    $new_diff = array_diff_assoc_recursive($value, $array2[$key]);
    if(    $new_diff != FALSE)
    {
    $difference[$key] = $new_diff;
    }
    }
    }
    elseif(!    array_key_exists($key, $array2) || $array2[$key] != $value)
    {
    $difference[$key] = $value;
    }
    }
    return !isset(    $difference) ? 0 : $difference;
    }
    ?>
    up
    17
    Michael Richey
    11 years ago
    If you're looking for a true array_diff_assoc, comparing arrays to determine the difference between two, finding missing values from both, you can use this along with array_merge.

    $a = array('a'=>1,'b'=>2,'c'=>3);
    $b = array('a'=>1,'b'=>2,'d'=>4);
    print_r(array_diff_assoc($a,$b));
    // returns:
    array
    (
    [c] => 3
    )

    print_r(array_diff_assoc($b,$a));
    // returns
    array
    (
    [d] => 4
    )

    print_r(array_merge(array_diff_assoc($a,$b),array_diff_assoc($b,$a)));
    // returns
    array
    (
    [c] => 3
    [d] => 4
    )
    up
    11
    chinello at gmail dot com
    17 years ago
    The following will recursively do an array_diff_assoc, which will calculate differences on a multi-dimensional level. This not display any notices if a key don't exist and if error_reporting is set to E_ALL:

    <?php
    function array_diff_assoc_recursive($array1, $array2)
    {
    foreach(    $array1 as $key => $value)
    {
    if(    is_array($value))
    {
    if(!isset(    $array2[$key]))
    {
    $difference[$key] = $value;
    }
    elseif(!    is_array($array2[$key]))
    {
    $difference[$key] = $value;
    }
    else
    {
    $new_diff = array_diff_assoc_recursive($value, $array2[$key]);
    if(    $new_diff != FALSE)
    {
    $difference[$key] = $new_diff;
    }
    }
    }
    elseif(!isset(    $array2[$key]) || $array2[$key] != $value)
    {
    $difference[$key] = $value;
    }
    }
    return !isset(    $difference) ? 0 : $difference;
    }
    ?>

    [NOTE BY danbrown AT php DOT net: This is a combination of efforts from previous notes deleted. Contributors included (Michael Johnson), (jochem AT iamjochem DAWT com), (sc1n AT yahoo DOT com), and (anders DOT carlsson AT mds DOT mdh DOT se).]
    up
    5
    dev5er6 at gmail dot com
    10 years ago
    Works more like the original function:

    <?php

    function array_diff_assoc_recursive ( )
    {
    $args = func_get_args ( );
    $diff = array ( );
    foreach (     array_shift ( $args ) as $key => $val )
    {
    for (     $i = 0, $j = 0, $tmp = array ( $val ) , $count = count ( $args ); $i < $count; $i++ )
    if (     is_array ( $val ) )
    if ( !isset (     $args[$i][$key] ) || !is_array ( $args[$i][$key] ) || empty( $args[$i][$key] ) )
    $j++;
    else
    $tmp[] = $args[$i][$key];
    elseif ( !     array_key_exists ( $key, $args[$i] ) || $args[$i][$key] !== $val )
    $j++;
    if (     is_array ( $val ) )
    {
    $tmp = call_user_func_array ( __FUNCTION__, $tmp );
    if ( ! empty (     $tmp ) ) $diff[$key] = $tmp;
    elseif (     $j == $count ) $diff[$key] = $val;
    }
    elseif (     $j == $count && $count ) $diff[$key] = $val;
    }

    return     $diff;
    }

    ?>
    up
    4
    tero dot lahtinen at iki dot fi
    6 years ago
    array_diff_assoc will fail, if a value is something that can not be converted to a string.
    up
    5
    benjamin at moonfactory dot co dot jp
    19 years ago
    Hi all,
    For php versions < 4.3...

    <?php
    /**
    * array_diff_assoc for version < 4.3
    **/
    if (!function_exists('array_diff_assoc'))
    {
    function     array_diff_assoc($a1, $a2)
    {
    foreach(    $a1 as $key => $value)
    {
    if(isset(    $a2[$key]))
    {
    if((string)     $value !== (string) $a2[$key])
    {
    $r[$key] = $value;
    }
    }else
    {
    $r[$key] = $value;
    }
    }
    return     $r ;
    }
    }

    ?>
    up
    6
    Alexander Podgorny
    18 years ago
    NOTE: the diff_array also removes all the duplicate values that match to the values in the second array:

    <?php
    $array1     = array("a","b","c","a","a");
    $array2 = array("a");

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

    // yields: array("b","c") the duplicate "a" values are removed
    ?>
    up
    3
    carl at thep dot lu dot se
    21 years ago
    To unset elements in an array if you know the keys but not the values, you can do:

    <?php
    $a     = array("foo", "bar", "baz", "quux");
    $b = array(1, 3); // Elements to get rid of

    foreach($b as $e)
    unset(    $a[$e]);
    ?>

    Of course this makes most sense if $b has many elements or is dynamically generated.
    up
    1
    news_yodpeirs at thoftware dot de
    13 years ago
    A quite simple (yet not very efficient) way to compare the first level of arrays which have values that are not strings:
    array_map('unserialize',array_diff_assoc(array_map('serialize',$arr1),array_map('serialize',$arr2)))
    Might be useful for debugging (that's what I use it for).
    up
    1
    jrajpu10 at gmail dot com
    15 years ago
    array_diff_assoc can also be used to find the duplicates in an array

    <?php
    $arr     = array('1','2','3','4','3','2','5');
    $uniques = array_unique($arr);
    // array_diff will not work here, array_diff_assoc works as it takes the key // in account.
    $dups = array_diff_assoc($arr, $uniques);

    print_r($dups);
    ?>

    Note: The index of the $dups is not in strict sequential order as expected by C programmer.
    up
    2
    cedric at daneel dot net
    17 years ago
    To diff between n-dimensional array, juste use this :

    <?php
    function array_diff_values($tab1, $tab2)
    {
    $result = array();
    foreach(    $tab1 as $values) if(! in_array($values, $tab2)) $result[] = $values;
    return     $result;
    }
    ?>
    up
    2
    spark dot crz at gmail dot com
    6 years ago
    Recursive implementation accepting multiple n-level-arrays as parameters:

    <?php
    function recursiveDiff() {
    $arrs = func_get_args();
    $first = array_shift($arrs);
    $diff = [];

    foreach(    $first as $key => $value) {
    $values = array_map(function($arr) use($key){
    if (    is_array($arr) && !array_key_exists($key, $arr))
    return     null;

    return     $arr[$key];
    },     $arrs);

    if (    in_array($value, $values))
    continue;

    if (    is_array($value)) {
    array_unshift($values, $value);
    $diff[$key] = call_user_func_array(__FUNCTION__, $values);
    continue;
    }

    $diff[$key] = $first[$key];
    }

    return     $diff;
    }
    ?>

    The other attempt was cleaner but didn't work for all cases.
    up
    1
    angujomondi at gmail dot com
    3 years ago
    For recursive diff of multiple arrays, exending solution provided by Gosh.

    <?php

    function array_diff_assoc_recursive(array $array, array ...$arrays)
    {
    $func = function($array1, $array2) use (&$func){
    $difference = [];
    foreach (    $array1 as $key => $value) {
    if (    is_array($value)) {
    if (!isset(    $array2[$key]) || !is_array($array2[$key])) {
    $difference[$key] = $value;
    } else {
    $new_diff = $func($value, $array2[$key]);
    if (!empty(    $new_diff)) {
    $difference[$key] = $new_diff;
    }
    }
    } else {
    if (!    array_key_exists($key, $array2) || $array2[$key] !== $value) {
    $difference[$key] = $value;
    }
    }
    }
    return     $difference;
    };
    $diffs = $array;
    foreach (    $arrays as $_array) {
    $diffs = $func($diffs, $_array);
    }
    return     $diffs;
    }

    ?>
    up
    0
    Henry
    6 months ago
    function array_diff_assoc_recursive($array1, $array2)
    {
    $array1Array = [];

    foreach ($array1 as $key => $value) {
    if (!is_array($value)) {
    continue;
    }
    $array1Array[$key] = $value;
    unset($array1[$key]);
    }

    $array2Array = [];

    foreach ($array2 as $key => $value) {
    if (!is_array($value)) {
    continue;
    }
    $array2Array[$key] = $value;
    unset($array2[$key]);
    }

    $diff = is_int(array_key_first($array1)) ? array_values(array_diff($array1, $array2)) : array_diff_assoc($array1, $array2);

    foreach ($array1Array as $key => $value) {
    if (isset($array2Array[$key])) {
    $subDiff = array_diff_assoc_recursive($value, $array2Array[$key]);
    if (count($subDiff) !== 0) {
    $diff = array_merge($diff, is_int($key) ? [$subDiff] : [$key => $subDiff]);
    }
    } else {
    $diff = array_merge($diff, is_int($key) ? [$value] : [$key => $value]);
    }
    }

    return $diff;
    }
    up
    0
    folurinyinka at gmail dot com
    2 years ago
    Recursive implementation accepting multiple n-level-arrays as parameters:

    ```php
    function recursiveDiff(...$arrays)
    {
    $first = array_shift($arrays);
    $diff = [];

    foreach ($first as $key => $value) {
    $values = array_map(function ($arr) use ($key) {
    if (is_array($arr) && !array_key_exists($key, $arr)) {
    return null;
    }

    return isset($arr[$key]) ? $arr[$key] : null;
    }, $arrs);

    if (in_array($value, $values)) {
    continue;
    }

    if (is_array($value)) {
    array_unshift($values, $value);
    $diff[$key] = call_user_func_array(__FUNCTION__, $values);
    continue;
    }

    $diff[$key] = $first[$key];
    }

    return $diff;
    }
    ```
    up
    -1
    nekto
    2 years ago
    PHP associative keys are case-sensitive, key "a" is different from key "A":

    <?php
    $arr     = ["A" => 666];
    var_dump($arr["a"]);
    var_dump($arr["A"]);
    ?>

    produces:
    NULL
    int(666)

    And in the same way, array_diff_assoc treats keys case-sensitively, and key "A" is not equal to key "a" and will be diffed:

    <?php
    // in arrays below value of "a" and "A" are the same, but keys are different
    // values of "b" are different
    // values of "c" are the same
    $compareWhat = ["a" => 666, "b" => 666, "c" => 666, ];
    $compareWith = ["A" => 666, "b" => 667, "c" => 666, ];

    var_dump(array_diff_assoc($compareWhat, $compareWith));
    ?>

    produces:
    array(2) {
    ["a"]=> int(666)
    ["b"]=> int(666)
    }

    And if the order of values in array is different, the order of the result will be different, although essentially the result stays the same:

    <?php
    // the same as above, but "b" comes before "a" in $compareWhat
    $compareWhat = ["b" => 666, "a" => 666, "c" => 666, ];
    $compareWith = ["A" => 666, "b" => 667, "c" => 666, ];

    var_dump(array_diff_assoc($compareWhat, $compareWith));
    ?>

    produces:
    array(2) {
    ["b"]=> int(666)
    ["a"]=> int(666)
    }
    up
    0
    shadow_games at abv dot bg
    10 years ago
    there is a functiont that i searched long enough now i have created it so someone else to find it if he need it ;]
    <?php
    function compare_two_object_recursive($object_1, $object_2, $object_1_Identifier = false, $object_2_Identifier = false){
    $object1 = (array)$object_1;
    $object2 = (array)$object_2;
    $object3 = array();

    $o1i = $object_1_Identifier ? $object_1_Identifier : 1;
    $o2i = $object_2_Identifier ? $object_2_Identifier : 2;

    foreach(    $object1 as $key => $value){
    if(    is_object($object1[$key])){
    $object1[$key] = (array)$object1[$key];
    $object2[$key] = (array)$object2[$key];
    $object3[$key] = (object)compare_two_object_recursive($object1[$key], $object2[$key], $o1i, $o2i);
    }elseif(    is_array($object1[$key])){
    $object3[$key] = compare_two_object_recursive($object1[$key], $object2[$key], $o1i, $o2i);
    }else{
    if(    $object1[$key] == $object2[$key]){
    $object3[$key]['comparison_status'] = "SAME";
    }else{
    $object3[$key]['comparison_status'] = "NOT THE SAME";
    $object3[$key][$o1i] = $object1[$key];
    $object3[$key][$o2i] = $object2[$key];
    }
    }
    }
    return     $object3;
    }
    ?>
    up
    -2
    spark dot crz at gmail dot com
    6 years ago
    Yet another recursive implementation, without if-else hell and with multiple parameters just like the original.

    <?php
    function recursiveDiff() {
    $arrs = func_get_args();
    $diff = call_user_func_array('array_diff_assoc', $arrs);

    foreach(    $diff as $key => $value) {
    if (!    is_array($value))
    continue;

    $children = array_map(function($arr) use($key){
    return     $arr[$key];
    },     $arrs);

    $diff[$key] = call_user_func_array(__FUNCTION__, $children);
    }

    return     $diff;
    }
    up
    -5
    francois-php at ceonizme dot fr
    9 years ago
    to chinello at gmail dot com
    I've had to use your function but it showed that the use of isset can't differentiate the NULL values from not setted values.

    Here's a version that takes care of this subtility.

    <?php
    function array_diff_assoc_recursive($array1, $array2)
    {
    $difference = NULL;
    foreach(    $array1 as $key => $value)
    {
    if(    is_array($value))
    {
    if(!    array_key_exists($key, $array2))
    {
    $difference[$key] = $value;
    }
    elseif(!    is_array($array2[$key]))
    {
    $difference[$key] = $value;
    }
    else
    {
    $new_diff = array_diff_assoc_recursive($value, $array2[$key]);
    if(    $new_diff != FALSE)
    {
    $difference[$key] = $new_diff;
    }
    }
    }
    elseif(!    array_key_exists($key, $array2) || $array2[$key] != $value)
    {
    $difference[$key] = $value;
    }
    }
    return !isset(    $difference) ? 0 : $difference;
    }
    ?>

    Hope that helps
    François
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