array_merge_recursive
(PHP 4 >= 4.0.1, PHP 5, PHP 7, PHP 8)
array_merge_recursive — 一つ以上の配列を再帰的にマージする
説明
array_merge_recursive() は、 一つ以上の配列の要素をマージし、 前の配列の最後にもう一つの配列の値を追加します。 マージした後の配列を返します。
入力配列が同じ文字列のキーを有している場合、 マージした後の配列ではこれらのキーの値がひとつにまとめられます。 この処理は再帰的に行われます。 このため、値の一つが配列自体を指している場合、 この関数は別の配列の対応するエントリもマージします。 しかし、配列が同じ数値キーを有している場合、 後の値は元の値を上書せず、追加されます。
パラメータ
arrays-
再帰的にマージしていく配列の可変リスト。
戻り値
すべての引数の配列をマージした結果の配列を返します。 引数なしで呼び出された場合、空の配列を返します。
変更履歴
| バージョン | 説明 |
|---|---|
| 7.4.0 | この関数は、引数なしでも呼び出せるようになりました。 このバージョンより前では、少なくともひとつの引数が必須でした。 |
例
例1 array_merge_recursive() の例
<?php
$ar1 = array("color" => array("favorite" => "red"), 5);
$ar2 = array(10, "color" => array("favorite" => "green", "blue"));
$result = array_merge_recursive($ar1, $ar2);
print_r($result);
?>上の例の出力は以下となります。
Array
(
[color] => Array
(
[favorite] => Array
(
[0] => red
[1] => green
)
[0] => blue
)
[0] => 5
[1] => 10
)
＋add a note
User Contributed Notes 38 notes
gabriel dot sobrinho at gmail dot com ¶
15 years ago
I refactored the Daniel's function and I got it:
<?php
/**
* array_merge_recursive does indeed merge arrays, but it converts values with duplicate
* keys to arrays rather than overwriting the value in the first array with the duplicate
* value in the second array, as array_merge does. I.e., with array_merge_recursive,
* this happens (documented behavior):
*
* array_merge_recursive(array('key' => 'org value'), array('key' => 'new value'));
* => array('key' => array('org value', 'new value'));
*
* array_merge_recursive_distinct does not change the datatypes of the values in the arrays.
* Matching keys' values in the second array overwrite those in the first array, as is the
* case with array_merge, i.e.:
*
* array_merge_recursive_distinct(array('key' => 'org value'), array('key' => 'new value'));
* => array('key' => array('new value'));
*
* Parameters are passed by reference, though only for performance reasons. They're not
* altered by this function.
*
* @param array $array1
* @param array $array2
* @return array
* @author Daniel <daniel (at) danielsmedegaardbuus (dot) dk>
* @author Gabriel Sobrinho <gabriel (dot) sobrinho (at) gmail (dot) com>
*/
function array_merge_recursive_distinct ( array &$array1, array &$array2 )
{
$merged = $array1;
foreach ( $array2 as $key => &$value )
{
if ( is_array ( $value ) && isset ( $merged [$key] ) && is_array ( $merged [$key] ) )
{
$merged [$key] = array_merge_recursive_distinct ( $merged [$key], $value );
}
else
{
$merged [$key] = $value;
}
}
return $merged;
}
?>
This fix the E_NOTICE when the the first array doesn't have the key and the second array have a value which is a array.
martyniuk dot vasyl at gmail dot com ¶
12 years ago
This is my version of array_merge_recursive without overwriting numeric keys:
<?php
function array_merge_recursive_new() {
$arrays = func_get_args();
$base = array_shift($arrays);
foreach ($arrays as $array) {
reset($base); //important
while (list($key, $value) = @each($array)) {
if (is_array($value) && @is_array($base[$key])) {
$base[$key] = array_merge_recursive_new($base[$key], $value);
} else {
$base[$key] = $value;
}
}
}
return $base;
}
?>
daniel at danielsmedegaardbuus dot dk ¶
15 years ago
<?php
/**
* array_merge_recursive does indeed merge arrays, but it converts values with duplicate
* keys to arrays rather than overwriting the value in the first array with the duplicate
* value in the second array, as array_merge does. I.e., with array_merge_recursive,
* this happens (documented behavior):
*
* array_merge_recursive(array('key' => 'org value'), array('key' => 'new value'));
* => array('key' => array('org value', 'new value'));
*
* array_merge_recursive_distinct does not change the datatypes of the values in the arrays.
* Matching keys' values in the second array overwrite those in the first array, as is the
* case with array_merge, i.e.:
*
* array_merge_recursive_distinct(array('key' => 'org value'), array('key' => 'new value'));
* => array('key' => array('new value'));
*
* Parameters are passed by reference, though only for performance reasons. They're not
* altered by this function.
*
* @param array $array1
* @param mixed $array2
* @return array
* @author daniel@danielsmedegaardbuus.dk
*/
function &array_merge_recursive_distinct(array &$array1, &$array2 = null)
{
$merged = $array1;
if (is_array($array2))
foreach ($array2 as $key => $val)
if (is_array($array2[$key]))
$merged[$key] = is_array($merged[$key]) ? array_merge_recursive_distinct($merged[$key], $array2[$key]) : $array2[$key];
else
$merged[$key] = $val;
return $merged;
}
?>
walf ¶
13 years ago
There are a lot of examples here for recursion that are meant to behave more like array_merge() but they don't get it quite right or are fairly customised. I think this version is most similar, takes more than 2 arguments and can be renamed in one place:
<?php
function array_merge_recursive_simple() {
if (func_num_args() < 2) {
trigger_error(__FUNCTION__ .' needs two or more array arguments', E_USER_WARNING);
return;
}
$arrays = func_get_args();
$merged = array();
while ($arrays) {
$array = array_shift($arrays);
if (!is_array($array)) {
trigger_error(__FUNCTION__ .' encountered a non array argument', E_USER_WARNING);
return;
}
if (!$array)
continue;
foreach ($array as $key => $value)
if (is_string($key))
if (is_array($value) && array_key_exists($key, $merged) && is_array($merged[$key]))
$merged[$key] = call_user_func(__FUNCTION__, $merged[$key], $value);
else
$merged[$key] = $value;
else
$merged[] = $value;
}
return $merged;
}
$a1 = array(
88 => 1,
'foo' => 2,
'bar' => array(4),
'x' => 5,
'z' => array(
6,
'm' => 'hi',
),
);
$a2 = array(
99 => 7,
'foo' => array(8),
'bar' => 9,
'y' => 10,
'z' => array(
'm' => 'bye',
11,
),
);
$a3 = array(
'z' => array(
'm' => 'ciao',
),
);
var_dump(array_merge($a1, $a2, $a3));
var_dump(array_merge_recursive_simple($a1, $a2, $a3));
var_dump(array_merge_recursive($a1, $a2, $a3));
?>
gives:
array(7) { array(7) { array(7) {
int(1) int(1) int(1)
["foo"]=> ["foo"]=> ["foo"]=>
array(1) { array(1) { array(2) {
[0]=> [0]=> [0]=>
int(8) int(8) int(2)
} } [1]=>
["bar"]=> ["bar"]=> int(8)
int(9) int(9) }
["x"]=> ["x"]=> ["bar"]=>
int(5) int(5) array(2) {
["z"]=> ["z"]=> [0]=>
array(1) { array(3) { int(4)
["m"]=> [0]=> [1]=>
string(4) "ciao" int(6) int(9)
} ["m"]=> }
[1]=> string(4) "ciao" ["x"]=>
int(7) [1]=> int(5)
["y"]=> int(11) ["z"]=>
int(10) } array(3) {
} [1]=> [0]=>
int(7) int(6)
["y"]=> ["m"]=>
int(10) array(3) {
} [0]=>
string(2) "hi"
[1]=>
string(3) "bye"
[2]=>
string(4) "ciao"
}
[1]=>
int(11)
}
[1]=>
int(7)
["y"]=>
int(10)
}
fantomx1 at gmail dot com ¶
8 years ago
I little bit improved daniel's and gabriel's contribution to behave more like original array_merge function to append numeric keys instead of overwriting them and added usefull option of specifying which elements to merge as you more often than not need to merge only specific part of array tree, and some parts of array just need to let overwrite previous. By specifying helper element mergeWithParent=true, that section of array will be merged, otherwise latter array part will override former. First level of array behave as classic array_merge.
function array_merge_recursive_distinct ( array &$array1, array &$array2 )
{
static $level=0;
$merged = [];
if (!empty($array2["mergeWithParent"]) || $level == 0) {
$merged = $array1;
}
foreach ( $array2 as $key => &$value )
{
if (is_numeric($key)) {
$merged [] = $value;
} else {
$merged[$key] = $value;
}
if ( is_array ( $value ) && isset ( $array1 [$key] ) && is_array ( $array1 [$key] )
) {
$level++;
$merged [$key] = array_merge_recursive_distinct($array1 [$key], $value);
$level--;
}
}
unset($merged["mergeWithParent"]);
return $merged;
}
thomas at n-o-s-p-a-m dot thoftware dot de ¶
16 years ago
This is a simple, three line approach.
Short description: If one of the Arguments isn't an Array, first Argument is returned. If an Element is an Array in both Arrays, Arrays are merged recursively, otherwise the element in $ins will overwrite the element in $arr (regardless if key is numeric or not). This also applys to Arrays in $arr, if the Element is scalar in $ins (in difference to the previous approach).
function array_insert($arr,$ins) {
# Loop through all Elements in $ins:
if (is_array($arr) && is_array($ins)) foreach ($ins as $k => $v) {
# Key exists in $arr and both Elemente are Arrays: Merge recursively.
if (isset($arr[$k]) && is_array($v) && is_array($arr[$k])) $arr[$k] = array_insert($arr[$k],$v);
# Place more Conditions here (see below)
# ...
# Otherwise replace Element in $arr with Element in $ins:
else $arr[$k] = $v;
}
# Return merged Arrays:
return($arr);
}
In Addition to felix dot ospald at gmx dot de in my opinion there is no need to compare keys with type-casting, as a key always is changed into an integer if it could be an integer. Just try
$a = array('1'=>'1');
echo gettype(key($a));
It will echo 'integer'. So for having Integer-Keys simply appended instead of replaced, add the Line:
elseif (is_int($k)) $arr[] = $v;
A Condition I used is:
elseif (is_null($v)) unset($arr[$k]);
So a NULL-Value in $ins will unset the correspondig Element in $arr (which is different to setting it to NULL!). This may be another Addition to felix dot ospald at gmx dot de: The absolute correct way to check for a Key existing in an Array is using array_key_exists() (not needed in the current context, as isset() is combined with is_array()). array_key_exists() will return TRUE even if the Value of the Element is NULL.
And the last one: If you want to use this approach for more than 2 Arrays, simply use this:
function array_insert_mult($arr) {
# More than 1 Argument: Append all Arguments.
if (func_num_args() > 1) foreach (array_slice(func_get_args(),1) as $ins) $arr = array_insert($arr,$ins);
# Return merged Arrays:
return($arr);
}
And if you worry about maintaining References: Simply use $ins[$k] instead of $v when assigning a Value/using a Value as Argument.
remy dot damour at -please-no-spam-laposte dot net ¶
15 years ago
If what you want is merge all values of your array that are arrays themselves to get a resulting array of depth one, then you're more looking for array_flatten function.
Unfortunately I did not find such native function in php, here is the one I wrote:
<?php
/**
* Flatten an array so that resulting array is of depth 1.
* If any value is an array itself, it is merged by parent array, and so on.
*
* @param array $array
* @param bool $preserver_keys OPTIONAL When true, keys are preserved when mergin nested arrays (=> values with same key get overwritten)
* @return array
*/
function array_flatten($array, $preserve_keys = false)
{
if (!$preserve_keys) {
// ensure keys are numeric values to avoid overwritting when array_merge gets called
$array = array_values($array);
}
$flattened_array = array();
foreach ($array as $k => $v) {
if (is_array($v)) {
$flattened_array = array_merge($flattened_array, call_user_func(__FUNCTION__, $v, $preserve_keys));
} elseif ($preserve_keys) {
$flattened_array[$k] = $v;
} else {
$flattened_array[] = $v;
}
}
return $flattened_array;
}
// example
$a = array ('k1' => 'a', 'k2' => array('k1' => 'b', 'k4' => array('k3' => 'c')));
var_export(array_flatten($a)); // output: array(0 => 'a', 1 => 'b', 2 => 'c')
var_export(array_flatten($a, true)); // output: array('k1' => 'b', 'k3' => 'c') // first 'k1' value gets overwritten by nested 'k1' value
?>
jonnybergstrom at googles mail domain dot comm ¶
15 years ago
This function didn't work for me - or it didn't do what I thought it would. So I wrote the below function, which merges two arrays, and returns the resulting array. The base array is the left one ($a1), and if a key is set in both arrays, the right value has precedence. If a value in the left one is an array and also an array in the right one, the function calls itself (recursion). If the left one is an array and the right one exists but is not an array, then the right non-array-value will be used.
*Any key only appearing in the right one will be ignored*
- as I didn't need values appearing only in the right in my implementation, but if you want that you could make some fast fix.
function array_merge_recursive_leftsource(&$a1, &$a2) {
$newArray = array();
foreach ($a1 as $key => $v) {
if (!isset($a2[$key])) {
$newArray[$key] = $v;
continue;
}
if (is_array($v)) {
if (!is_array($a2[$key])) {
$newArray[$key] = $a2[$key];
continue;
}
$newArray[$key] = array_merge_recursive_leftsource($a1[$key], $a2[$key]);
continue;
}
$newArray[$key] = $a2[$key];
}
return $newArray;
}
spambegone at cratemedia dot com ¶
16 years ago
I've tried these array_merge_recursive functions without much success. Maybe it's just me but they don't seem to actually go more than one level deep? As with all things, its usually easier to write your own, which I did and it seems to work just the way I wanted. Anyways, my function hasn't been tested extensively, but it's a simple function, so in hopes that this might be useful to someone else I'm sharing.
Also, the PHP function array_merge_recursive() didn't work for my purposes because it didn't overwrite the values like I needed it to. You know how it works, it just turns it into an array with multiple values... not helpful if your code is expecting one string.
function array_merge_recursive_unique($array1, $array2) {
// STRATEGY
/*
Merge array1 and array2, overwriting 1st array values with 2nd array
values where they overlap. Use array1 as the base array and then add
in values from array2 as they exist.
Walk through each value in array2 and see if a value corresponds
in array1. If it does, overwrite with second array value. If it's an
array, recursively execute this function and return the value. If it's
a string, overwrite the value from array1 with the value from array2.
If a value exists in array2 that is not found in array1, add it to array1.
*/
// LOOP THROUGH $array2
foreach($array2 AS $k => $v) {
// CHECK IF VALUE EXISTS IN $array1
if(!empty($array1[$k])) {
// IF VALUE EXISTS CHECK IF IT'S AN ARRAY OR A STRING
if(!is_array($array2[$k])) {
// OVERWRITE IF IT'S A STRING
$array1[$k]=$array2[$k];
} else {
// RECURSE IF IT'S AN ARRAY
$array1[$k] = array_merge_recursive_unique($array1[$k], $array2[$k]);
}
} else {
// IF VALUE DOESN'T EXIST IN $array1 USE $array2 VALUE
$array1[$k]=$v;
}
}
unset($k, $v);
return $array1;
}
brian at vermonster dot com ¶
20 years ago
Here is a fairly simple function that replaces while recursing.
<?php
/**
* array_merge_recursive2()
*
* Similar to array_merge_recursive but keyed-valued are always overwritten.
* Priority goes to the 2nd array.
*
* @static yes
* @public yes
* @param $paArray1 array
* @param $paArray2 array
* @return array
*/
function array_merge_recursive2($paArray1, $paArray2)
{
if (!is_array($paArray1) or !is_array($paArray2)) { return $paArray2; }
foreach ($paArray2 AS $sKey2 => $sValue2)
{
$paArray1[$sKey2] = array_merge_recursive2(@$paArray1[$sKey2], $sValue2);
}
return $paArray1;
}
?>
Examples:
<?php
$array1 = array(
'liquids' => array(
'water' => array('cold', 'fizzy', 'clean')
,'beer' => 'warm'
)
);
$array2 = array(
'liquids' => array(
'water' => 'hot'
,'milk' => 'wet'
)
);
$result1 = array_merge_recursive2($array1, $array2);
$result2 = array_merge_recursive2($array2, $array1);
?>
Result 1 is:
Array
(
[liquids] => Array
(
[water] => hot
[beer] => warm
[milk] => wet
)
)
Result 2 is:
Array
(
[liquids] => Array
(
[water] => Array
(
[0] => cold
[1] => fizzy
[2] => clean
)
[milk] => wet
[beer] => warm
)
)
mark dot roduner at gmail dot com ¶
14 years ago
<?php
/**
* Merges any number of arrays / parameters recursively, replacing
* entries with string keys with values from latter arrays.
* If the entry or the next value to be assigned is an array, then it
* automagically treats both arguments as an array.
* Numeric entries are appended, not replaced, but only if they are
* unique
*
* calling: result = array_merge_recursive_distinct(a1, a2, ... aN)
**/
function array_merge_recursive_distinct () {
$arrays = func_get_args();
$base = array_shift($arrays);
if(!is_array($base)) $base = empty($base) ? array() : array($base);
foreach($arrays as $append) {
if(!is_array($append)) $append = array($append);
foreach($append as $key => $value) {
if(!array_key_exists($key, $base) and !is_numeric($key)) {
$base[$key] = $append[$key];
continue;
}
if(is_array($value) or is_array($base[$key])) {
$base[$key] = array_merge_recursive_distinct($base[$key], $append[$key]);
} else if(is_numeric($key)) {
if(!in_array($value, $base)) $base[] = $value;
} else {
$base[$key] = $value;
}
}
}
return $base;
}
?>
andyidol at gmail dot com ¶
13 years ago
Here's my function to recursively merge two arrays with overwrites. Nice for merging configurations.
<?php
function MergeArrays($Arr1, $Arr2)
{
foreach($Arr2 as $key => $Value)
{
if(array_key_exists($key, $Arr1) && is_array($Value))
$Arr1[$key] = MergeArrays($Arr1[$key], $Arr2[$key]);
else
$Arr1[$key] = $Value;
}
return $Arr1;
}
?>
andrew at indigo - sphere dot co dot uk ¶
4 years ago
An alternative solution where this function does not produce the desired output: Pass a custom recursive function to array_reduce():
For example (Using PHP 7 capabilities to create recursive anonymous function):
<?php
function array_merge_recursive(...$arrays): ?array {
return array_reduce($arrays, new class {
public function __invoke($carry, $item) {
if (is_array($carry) && is_array($item) {
return $this($carry, $item);
}
return $item ?: $carry;
}
}
}
?>
In this case truthy values will overwrite the value in the previous array.
Of course this is presented as a simple example only, and is not a general solution.
robert dot schlak at alcatel-lucent dot com ¶
12 years ago
The presence of NULLs; here is an example of the issue and a fix. Although it may not be apparent, if using array_merge_recursive in a loop to combine results from a database query or some other function, you can corrupt your result when NULLs are present in the data. I discovered this when migrating from an Oracle DB to a MySQL DB. I had to match the array structure returned from the PHP function calling the DB and got bit. The array_walk call fixed this for me.
This is a simple example that lacks any DB calls and looping. Assume your array had the DB column names (first, last, and age) and you needed to combine the data in a multi-dimensional array in which the column name is an array key with all rows beneath it. The corruption occurs in $a3. If using element position 2, one could create the fictitious 'pete johnson' because of the collapsing of elements.
<?php
print "<pre>Show corruption\\n";
$a1 = array('first'=>'bob', 'last'=>'jones', 'age'=>'48');
$a2 = array('first'=>'sam', 'last'=>'smith', 'age'=>'41');
$a3 = array('first'=>'pete', 'last'=>null, 'age'=>'3');
$a4 = array('first'=>'joe', 'last'=>'johnson', 'age'=>'33');
$a5 = array_merge_recursive($a1,$a2,$a3,$a4);
print_r($a5);
print "Show Fix\\n";
$a1 = array('first'=>'bob', 'last'=>'jones', 'age'=>'48');
$a2 = array('first'=>'sam', 'last'=>'smith', 'age'=>'41');
$a3 = array('first'=>'pete', 'last'=>null, 'age'=>'3');
array_walk($a3, 'null_to_empty');
$a4 = array('first'=>'joe', 'last'=>'johnson', 'age'=>'33');
$a5 = array_merge_recursive($a1,$a2,$a3,$a4);
print_r($a5);
print "</pre>\\n";
function null_to_empty(&$item) {
$item = is_null($item) ? '' : $item;
}
?>
miniscalope at gmail dot com ¶
15 years ago
I would merge 2 arrays but keep the values unique in the result array.
I hope this will help...
<?php
function array_merge_recursive_unique($array1, $array2) {
foreach($array2 AS $k => $v) {
if(!isset($array1[$k]))
{
$array1[$k] = $v;
}
else
{
if(!is_array($v)){
if(is_array($array1[$k]))
{
if(!in_array($v,$array1[$k]))
{
$array1[$k][] = $v;
}
}
else
{
if($array1[$k] != $v)
$array1[$k] = array($array1[$k], $v);
}
}
else
{
$array1[$k] = array_merge_recursive_unique($array1,$array2[$k]);
}
}
}
unset($k, $v);
return $array1;
}
?>
paha at paha dot hu ¶
17 years ago
In this version the values are overwritten only if they are not an array. If the value is an array, its elements will be merged/overwritten:
// array_merge_recursive which override value with next value.
// based on: http://www.php.net/manual/hu/function.array-merge-recursive.php 09-Dec-2006 03:38
function array_merge_recursive_unique($array0, $array1)
{
$arrays = func_get_args();
$remains = $arrays;
// We walk through each arrays and put value in the results (without
// considering previous value).
$result = array();
// loop available array
foreach($arrays as $array) {
// The first remaining array is $array. We are processing it. So
// we remove it from remaing arrays.
array_shift($remains);
// We don't care non array param, like array_merge since PHP 5.0.
if(is_array($array)) {
// Loop values
foreach($array as $key => $value) {
if(is_array($value)) {
// we gather all remaining arrays that have such key available
$args = array();
foreach($remains as $remain) {
if(array_key_exists($key, $remain)) {
array_push($args, $remain[$key]);
}
}
if(count($args) > 2) {
// put the recursion
$result[$key] = call_user_func_array(__FUNCTION__, $args);
} else {
foreach($value as $vkey => $vval) {
$result[$key][$vkey] = $vval;
}
}
} else {
// simply put the value
$result[$key] = $value;
}
}
}
}
return $result;
}
phil dot kemmeter at gmail dot com ¶
16 years ago
I've edit this version even a little bit more, so that the function does not override any values, but inserts them at a free key in the array:
function my_array_merge ($arr,$ins) {
if(is_array($arr))
{
if(is_array($ins)) foreach($ins as $k=>$v)
{
if(isset($arr[$k])&&is_array($v)&&is_array($arr[$k]))
{
$arr[$k] = my_array_merge($arr[$k],$v);
}
else {
// This is the new loop :)
while (isset($arr[$k]))
$k++;
$arr[$k] = $v;
}
}
}
elseif(!is_array($arr)&&(strlen($arr)==0||$arr==0))
{
$arr=$ins;
}
return($arr);
}
Example:
$array1 = array(
100 => array(30),
200 => array(20, 30)
);
$array2 = array(
100 => array(40),
201 => array(60, 30)
);
print_r(my_array_merge($array1,$array2));
Output with array_merge_recursive:
Array
(
[0] => Array
(
[0] => 30
)
[1] => Array
(
[0] => 20
[1] => 30
)
[2] => Array
(
[0] => 40
)
)
This is not the result, I expect from a MERGE-Routine...
Output with the current function:
Array
(
[100] => Array
(
[0] => 30
[1] => 40
)
[200] => Array
(
[0] => 20
[1] => 30
)
)
This is what I want :)