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array_diff_assoc

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

array_diff_assoc追加された添字の確認を含めて配列の差を計算する

説明

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

arrayarrays と比較し、 その差を返します。array_diff() とは異なり、 配列のキーも用いて比較を行います。

パラメータ

array

比較元の配列。

arrays

比較する対象となる配列。

戻り値

array の要素のうち、 その他の配列のいずれにも含まれないものだけを残した配列を返します。

変更履歴

バージョン 説明
8.0.0 この関数は、引数をひとつだけ渡しても呼び出せるようになりました。 これより前のバージョンでは、少なくともふたつの引数が必須でした。

例1 array_diff_assoc() の例

この例で、"a" => "green" の組が両方の配列に現れており、 このため、この関数の出力には含まれていません。 これとは異なり、0 => "red" は出力の中に現れています。 これは、最初の配列の "red" のキーには自動的に 0 が割り当てられる一方で、 二番目の配列では 0 には既に yellow というキーがあるため、 "red" には 1 が割り当てられるためです。

<?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);
?>

上の例の出力は以下となります。

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

例2 array_diff_assoc() の例

key => value の組からの二つの値は、 (string) $elem1 === (string) $elem2 が成り立つ場合のみ等しいと見なされます。 言い替えると、厳密なチェックが行われるため、 文字列表現が同じである必要があります。

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

上の例の出力は以下となります。

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

注意

注意: この関数は、N 次元配列の一次元だけを調べます。例えば array_diff_assoc($array1[0], $array2[0]); とすることにより、より深い次元でチェックを行うことも可能です。

注意: 同様の配列で、より多くのキーがあるものを比較するときには、引数を正しい順で渡すようにしましょう。 新しい配列が、リストの先頭になければいけません。

参考

  • array_diff() - 配列の差を計算する
  • array_diff_uassoc() - ユーザーが指定したコールバック関数を利用し、 追加された添字の確認を含めて配列の差を計算する
  • array_udiff_assoc() - データの比較にコールバック関数を用い、 追加された添字の確認を含めて配列の差を計算する
  • array_udiff_uassoc() - データと添字の比較にコールバック関数を用い、 追加された添字の確認を含めて配列の差を計算する
  • array_intersect() - 配列の共通項を計算する
  • array_intersect_assoc() - 追加された添字の確認も含めて配列の共通項を確認する

add a note

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
16 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
10 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
9 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
17 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
20 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 $b has many elements or is dynamically generated.
up
1
news_yodpeirs at thoftware dot de
12 years ago
A quite simple (yet not very efficient) way to compare the first level of arrays which have values that are not strings:
array_map('unserialize',array_diff_assoc(array_map('serialize',$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
16 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
5 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
0
Henry
27 days 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
1 year 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
0
angujomondi at gmail dot com
2 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
-1
nekto
1 year 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
9 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
5 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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