array_diff_assoc

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

array_diff_assoc — 带索引检查计算数组的差集

说明

array_diff_assoc ( array $array1 , array $array2 [, array $... ] ) : array

array_diff_assoc() 返回一个数组，该数组包括了所有在 array1 中但是不在任何其它参数数组中的值。注意和 array_diff() 不同的是键名也用于比较。

参数

array1

从这个数组进行比较

array2

被比较的数组

...

更多被比较的数组

返回值

Returns an array containing all the values from array1 that are not present in any of the other arrays.

范例

Example #1 array_diff_assoc() 例子

上面的例子中可以看到键值对 "a" => "green" 在两个数组中都有，因此不在本函数的输出中。与此不同，键值对 0 => "red" 出现在输出中是因为第二个参数中的 "red" 的键名是 1。

<?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);
?>

以上例程会输出：

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

Example #2 array_diff_assoc() example

键值对 key => value 中的两个值仅在 (string) $elem1 === (string) $elem2 时被认为相等。也就是说使用了严格检查，字符串的表达必须相同。

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

以上例程会输出：

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

注释

Note: 注意本函数只检查了多维数组中的一维。当然可以用 array_diff_assoc($array1[0], $array2[0]); 检查更深的维度。

Note: 使用更多的键比较相似数组时，确保你传入参数的顺序是正确的。 新的数组应该是在列表里的第一个。

参见

User Contributed Notes

spark dot crz at gmail dot com 02-Apr-2018 04:56
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.
spark dot crz at gmail dot com 02-Apr-2018 03:29
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;
}
tero dot lahtinen at iki dot fi 10-Oct-2017 03:23
array_diff_assoc will fail, if a value is something that can not be converted to a string.
francois-php at ceonizme dot fr 28-Aug-2014 06:27
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
Fran?ois
shadow_games at abv dot bg 11-Jun-2014 03:45
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;
    }
?>
dev5er6 at gmail dot com 13-Apr-2014 04:01
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;
}

?>
telefoontoestel at hotmail dot com 04-Feb-2014 09:11
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;
}
?>
Michael Richey 04-May-2013 01:43
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
)
Giosh 15-Mar-2013 11:15
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
  }
}
news_yodpeirs at thoftware dot de 12-Jul-2011 04:25
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).
jrajpu10 at gmail dot com 25-Oct-2008 12:57
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.
cedric at daneel dot net 21-May-2007 06:01
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;
    }
?>
contact at pascalopitz dot com 11-Apr-2007 04:14
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
)
chinello at gmail dot com 18-Mar-2007 10:33
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).]
Alexander Podgorny 30-May-2006 02:30
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
?>
benjamin at moonfactory dot co dot jp 11-Jan-2005 09:56
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 ;
    }
}

?>
carl at thep dot lu dot se 09-May-2003 02:55
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.