文字

array_merge_recursive

(PHP 4 >= 4.0.1, PHP 5, PHP 7)

array_merge_recursive — 递归地合并一个或多个数组

说明

array array_merge_recursive ( array $array1 [, array $... ] )

array_merge_recursive() 将一个或多个数组的单元合并起来，一个数组中的值附加在前一个数组的后面。返回作为结果的数组。

如果输入的数组中有相同的字符串键名，则这些值会被合并到一个数组中去，这将递归下去，因此如果一个值本身是一个数组，本函数将按照相应的条目把它合并为另一个数组。然而，如果数组具有相同的数组键名，后一个值将不会覆盖原来的值，而是附加到后面。

参数

array1: 要合并的初始数组。
...: 数组变量列表，进行递归合并。

返回值

一个结果数组，其中的值合并自附加的参数。

范例

Example #1 array_merge_recursive() 例子

  <?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 );
 ?>

以上例程会输出：

Array
(
    [color] => Array
        (
            [favorite] => Array
                (
                    [0] => red
                    [1] => green
                )            [0] => blue
        )    [0] => 5
    [1] => 10
)

参见

array_merge() - 合并一个或多个数组

用户评论:

[#1] Anonymous [2015-11-30 21:45:55]

Proper simplistic example:

<?php $Array1 = [1, 2]; $Array2 = [3, 4]; echo implode("<br>", array_merge_recursive($Array1, $Array2)); ?>

Output:
1
2
3
4

[#2] Orhan POLAT [2015-06-18 14:24:53]

Merging arrays recursively some problem about existing keys, so that i wrote the function above like this:

function merge($array0, $array1) {
  // Result
  $merged = array();

  foreach (func_get_args() as $array) {
   // Check incoming argument is array
   if (is_array($array)) {
    foreach ($array as $key => $value) {
     // Check there is an array with the key: $key
     if (isset($merged[$key])) {
      // Check the value is array
      if (is_array($value)) {
       // So we must merge current value with the existing array
       $merged[$key] = call_user_func_array(__FUNCTION__, $merged[$key], $value);
      } else {
       if (!is_array($merged[$key])) {
        // If the existing array with the key: $key not an array
        // We make it an array
        $merged[$key] = array($merged[$key]);
       }

       // And add the current value
       $merged[$key][] = $value;
      }
     } else {
      // If not exists make the array
      $merged[$key] = $value;
     }
    }
   }
  }

  return $merged;
}

[#3] Anonymous [2015-03-17 17:00:58]

Attention.
(used PHP 5.4. XAMPP)

Values with numeric keys are always appended.   The index of the merge array is determined by the startindex of the first array. Value4s with numeric keys seems always appended.
If a key looks like an integer, array_merge_recursive will interpret the string as an number.

In the example  $arr['farbe']['22'] = 'gr??n' wil be found after array_merge_recursive in $res['farbe'][33]

$ar1 = array("farbe" => array (31 => 'holla', "rot", "favorit" => "gelb2"), "favorit" => "gelb1", 5);
$ar2 = array(10, "farbe" => array ('22' => "gr??n",  "favorit" => 2, "blau"));
$result = array_merge_recursive ($ar1, $ar2);
var_dump($result);
echo('<hr>');

// var_dump
array(4) {
  ["farbe"]=>
  array(5) {
    [31]=>
    string(5) "holla"
    [32]=>
    string(3) "rot"
    ["favorit"]=>
    array(2) {
      [0]=>
      string(5) "gelb2"
      [1]=>
      int(2)
    }
    [33]=>
    string(5) "gr??n"
    [34]=>
    string(4) "blau"
  }
  ["favorit"]=>
  string(5) "gelb1"
  [0]=>
  int(5)
  [1]=>
  int(10)
}

[#4] php at metehanarslan dot com [2014-06-12 22:52:11]

Sometimes you need to modify an array with another one here is my approach to replace an array's content recursively with delete opiton. Here i used "::delete::" as reserved word to delete items.

<?php $person= array( "name" => "Metehan", "surname"=>"Arslan", "age"=>27, "mail"=>"hidden", "favs" => array( "language"=>"php", "planet"=>"mercury", "city"=>"istanbul") ); $newdata = array( "age"=>28, "mail"=>"::delete::", "favs" => array( "language"=>"js", "planet"=>"mercury", "city"=>"shanghai") ); print_r(array_overlay($person,$newdata)); // result: Array ( [name] => Metehan [surname] => Arslan [age] => 28 [favs] => Array ( [language] => js [planet] => mercury [city] => shanghai ) ) function array_overlay($a1,$a2) { foreach($a1 as $k => $v) { if ($a2[$k]=="::delete::"){ unset($a1[$k]); continue; }; if(!array_key_exists($k,$a2)) continue; if(is_array($v) && is_array($a2[$k])){ $a1[$k] = array_overlay($v,$a2[$k]); }else{ $a1[$k] = $a2[$k]; } } return $a1; } ?>

[#5] cezarion at cezarion dot net [2014-04-09 12:22:22]

An updated version of  array_merge_recursive without overwriting numeric keys from martyniuk :
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], $value);
                } else {
                    if(isset($base[$key]) && is_int($key)) {
                      $key++;
                    }
                    $base[$key] = $value;
                }
            }
        }

    return $base;
  }

[#6] robert dot schlak at alcatel-lucent dot com [2012-07-02 16:39:59]

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; } ?>

[#7] martyniuk dot vasyl at gmail dot com [2011-12-24 09:10:40]

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; } ?>

[#8] walf [2011-05-25 22:23:22]

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)
                                                }

[#9] andyidol at gmail dot com [2011-02-10 19:14:21]

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; } ?>

[#10] lsiq at papotam com [2010-10-01 13:17:51]

<?php // this function merges an array with the $_SESSION // if you omit second parameter it merges to the root // if you give one 'path' array it is merged deeply function arr2sess($arr, $path=array()){ if (!is_array($arr)) return false; foreach($arr as $k => $v){ if(is_array($arr[$k])) { $path[] = $k; arr2sess($arr[$k], $path); }else{ $ref = &$_SESSION; if($path){ foreach($path as $val){ if(!$ref[$val]) $ref[$val] = array(); $ref = &$ref[$val]; } } $ref[$k] = $v; } } } session_start(); $x = array(k1=>12, k2=>array(kxx=>'forget me', kyy=>'I was allways here')); // do you have any of this on $_SESSION $rpl = array(k2=>array(kxx=>'I am a replaced value',kzz=>'I am a new value')); arr2sess($x, array('deep','deep','in_session')); // you can use this way arr2sess($x); // or this arr2sess($rpl); // to merge parts with the $_SESSION $w = array(120, q=>array(199,100)); // works the same way on numeric keys arr2sess($w, array('one','two')); arr2sess($w); echo '<pre>'; print_r($_SESSION); ?>

[#11] mark dot roduner at gmail dot com [2010-02-13 23:34:48]

<?php 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; } ?>

[#12] drvali at hotmail dot com [2009-10-05 21:31:59]

<?php function array_merge_replace_recursive() {     // Holds all the arrays passed     $params = & func_get_args ();          // First array is used as the base, everything else overwrites on it     $return = array_shift ( $params );          // Merge all arrays on the first array     foreach ( $params as $array ) {         foreach ( $array as $key => $value ) {             // Numeric keyed values are added (unless already there)             if (is_numeric ( $key ) && (! in_array ( $value, $return ))) {                 if (is_array ( $value )) {                     $return [] = $this->array_merge_replace_recursive ( $return [$$key], $value );                 } else {                     $return [] = $value;                 }                              // String keyed values are replaced             } else {                 if (isset ( $return [$key] ) && is_array ( $value ) && is_array ( $return [$key] )) {                     $return [$key] = $this->array_merge_replace_recursive ( $return [$$key], $value );                 } else {                     $return [$key] = $value;                 }             }         }     }          return $return; } $a = array (     "a" => 1,     "b" => 2,     'foo',     'bar' ); $b = array (     "a" => 2,     "c" => 3,     'foo' ); $c = array_merge_replace_recursive ( $a, $b ); print_r ( $a ); print_r ( $b ); print_r ( $c ); ?>

Output:
Array
(
    [a] => 1
    [b] => 2
    [0] => foo
    [1] => bar
)
Array
(
    [a] => 2
    [c] => 3
    [0] => foo
)
Array
(
    [a] => 2
    [b] => 2
    [0] => foo
    [1] => bar
    [c] => 3
)

[#13] gabriel dot sobrinho at gmail dot com [2009-07-13 19:56:31]

I refactored the Daniel's function and I got it:

<?php 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.

[#14] jonnybergstrom at googles mail domain dot comm [2009-06-27 08:30:20]

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;
}

[#15] michiel at synetic dot nl [2009-05-22 01:54:20]

A small improvement upon the previously posted array_merge_recursive_distinct functions (based on daniel's version). This implementation preserves the parameter input from the original, you can pass an infinite amount of array's to merge.

<?php function &array_merge_recursive_distinct() { $aArrays = func_get_args(); $aMerged = $aArrays[0]; for($i = 1; $i < count($aArrays); $i++) { if (is_array($aArrays[$i])) { foreach ($aArrays[$i] as $key => $val) { if (is_array($aArrays[$i][$key])) { $aMerged[$key] = is_array($aMerged[$key]) ? PR::array_merge_recursive_distinct($aMerged[$key], $aArrays[$i][$key]) : $aArrays[$i][$key]; } else { $aMerged[$key] = $val; } } } } return $aMerged; } ?>

[#16] daniel at danielsmedegaardbuus dot dk [2009-03-19 02:18:21]

<?php 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; } ?>

[#17] miniscalope at gmail dot com [2009-02-04 03:56:26]

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; } ?>

[#18] remy dot damour at -please-no-spam-laposte dot net [2009-01-21 06:28:33]

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 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 ?>

[#19] phil dot kemmeter at gmail dot com [2008-12-08 10:45:57]

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 :)

[#20] scott dot clark at vizioninteractive dot com [2008-08-28 13:55:34]

Needed some way to fuse two arrays together and found a function here (below from thomas) and decided to update it even further to be a little more smart.

<?php 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 $arr[$k] = $v; } } elseif(!is_array($arr)&&(strlen($arr)==0||$arr==0)) { $arr=$ins; } return($arr); } ?>

[#21] thomas at n-o-s-p-a-m dot thoftware dot de [2008-05-04 18:50:03]

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.

[#22] felix dot ospald at gmx dot de [2008-02-26 11:23:46]

If you desire correct and performant behaviour (in contrast to the other postings) use this code. It works as documented above.
If you want that keys are always perserved and not appended or renumbered if they are numeric comment out the "if (((string) $key) === ((string) intval($key)))" case.
@spambegone at cratemedia dot com: using empty is not right way to check if an item is in the array use isset!

<?php function array_merge_recursive2($array1, $array2) { $arrays = func_get_args(); $narrays = count($arrays); // check arguments // comment out if more performance is necessary (in this case the foreach loop will trigger a warning if the argument is not an array) for ($i = 0; $i < $narrays; $i ++) { if (!is_array($arrays[$i])) { // also array_merge_recursive returns nothing in this case trigger_error('Argument #' . ($i+1) . ' is not an array - trying to merge array with scalar! Returning null!', E_USER_WARNING); return; } } // the first array is in the output set in every case $ret = $arrays[0]; // merege $ret with the remaining arrays for ($i = 1; $i < $narrays; $i ++) { foreach ($arrays[$i] as $key => $value) { if (((string) $key) === ((string) intval($key))) { // integer or string as integer key - append $ret[] = $value; } else { // string key - megre if (is_array($value) && isset($ret[$key])) { // if $ret[$key] is not an array you try to merge an scalar value with an array - the result is not defined (incompatible arrays) // in this case the call will trigger an E_USER_WARNING and the $ret[$key] will be null. $ret[$key] = array_merge_recursive2($ret[$key], $value); } else { $ret[$key] = $value; } } } } return $ret; } // Examples: print_r(array_merge_recursive2(array('A','B','C' => array(1,2,3)), array('D','C' => array(1,4)))); print_r(array_merge_recursive2(array('A','B','0' => array(1,2,3)), array('D','0' => array(1,array(4))))); print_r(array_merge_recursive2(array('A' => array('A' => 1)), array('A' => array('A' => array(2))))); var_dump(array_merge_recursive2(array('A' => array('A' => 2)), array('A' => array('A' => null)))); ?>

[#23] spambegone at cratemedia dot com [2008-02-12 02:06:38]

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

// 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;
}

[#24] paha at paha dot hu [2007-03-12 12:02:31]

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;
}

[#25] randallgirard at hotmail dot com [2006-11-26 13:18:24]

I wrote the following for merging arrays, in my project mainly for configuration... Thought someone else might find it usefull.

function array_merge_recursive_keys( $first, $second, $greedy=false) {
   $inter = array_intersect_assoc(array_keys($first), array_keys($second)); # shaired keys
# the idea next, is to strip and append from $second into $first
   foreach ( $inter as $key ) {
   # recursion if both are arrays
      if ( is_array($first[$key]) && is_array($second[$key]) ) {
         $first[$key] = array_merge_recursive_keys($first[$key], $second[$key]);
      }
   # non-greedy array merging:
      else if ( is_array($first[$key] && !$greedy ) ) {
         $first[$key][] = $second[$key];
      }
      else if ( is_array($second[$key]) && !$greedy ) {
         $second[$key][] = $first[$key];
         $first[$key] = $second[$key];
      }
   # overwrite...
      else {
         $first[$key] = $second[$key];
      }
      unset($second[$key]);
   }
# merge the unmatching keys onto first
   return array_merge($first, $second);
}

[#26] thiago dot mata at yahoo dot com dot br [2006-09-30 12:25:16]

<?php function array_merge_recursive_keep_keys( $arrElement1 , $arrElement2 , $intCount = 0 ) { $arrNew = array(); $arrElement1Keys = array_keys( $arrElement1 ); $arrElement2Keys = array_keys( $arrElement2 ); $arrDifKeys1 = array_diff( $arrElement1Keys, $arrElement2Keys ); $arrDifKeys2 = array_diff( $arrElement2Keys, $arrElement1Keys ); $arrInter = array_intersect( $arrElement1Keys , $arrElement2Keys ); foreach( $arrDifKeys1 as $strKey1) { $arrNew[ $strKey1 ] = $arrElement1[ $strKey1 ]; } foreach( $arrDifKeys2 as $strKey2) { $arrNew[ $strKey2 ] = $arrElement2[ $strKey2 ]; } foreach( $arrInter as $strInterKey ) { if( is_array( $arrElement1[ $strInterKey ] ) && is_array( $arrElement2[ $strInterKey ] ) ) { $intCount++; $arrNew[ $strInterKey ] = array_merge_recursive_keep_keys( $arrElement1[ $strInterKey ] , $arrElement2[ $strInterKey ] , $intCount ); } elseif( is_array( $arrElement1[ $strInterKey ] ) || is_array( $arrElement2[ $strInterKey ] ) ) { $arrNew[ $strInterKey ][] = $arrElement1[ $strInterKey ]; $arrNew[ $strInterKey ][] = $arrElement2[ $strInterKey ]; } else { $arrNew[ $strInterKey ] = array(); $arrNew[ $strInterKey ][] = $arrElement1[ $strInterKey ]; $arrNew[ $strInterKey ][] = $arrElement2[ $strInterKey ]; } } return $arrNew; } ?>

[#27] smilingrasta [2006-07-07 10:04:16]

This function tends to reindex arrays, which is not mentioned in the function description.

I just tried to run that function on a three dimensional array, containing errormessages.
The first dim. contains the severity of the error ('warn', 'crit') the second dim the linenumber (numerical) and the third one consists of errormessages

<?php # Array printout: Array ( [warn] => Array // severity (associative) ( [2] => Array // linenumber (numerical) ( [0] => "Category does not exist" [1] => "Manufacturer does not exist" ) ) ) ?>

If i now merge two or more of those arrays using array_merge_recursive(), the linenumbers are not conserved. Instead of, they are all renumbered, starting with 0.

Just thought anyone may want to know about that. :)
regards, smilingrasta

[#28] manicdepressive at mindless dot com [2004-06-22 07:30:43]

Please be aware that under circumstances where you have
both the key and value common between the two arrays at a given node,
array_merge_recursive() will behave differently if that value is NULL,
as opposed to a non-null value.

i.e., I expected the results of the first two sections below to
have the same structure, but they don't.
If this might apply to you, please see for yourself.

<pre><?php $a1 = array('a'=>'b'); $a2 = array('a'=>'b'); $a3 = array_merge_recursive($a1,$a2); var_export($a3); echo "\n\n"; $a1 = array('a'=>NULL); $a2 = array('a'=>NULL); $a3 = array_merge_recursive($a1,$a2); var_export($a3); echo "\n\n"; $a1 = array('a'=>'b'); $a2 = array('a'=>NULL); $a3 = array_merge_recursive($a1,$a2); var_export($a3); echo "\n\n"; ?></pre>

This behavior also occurs if the value is the empty array.
In fact, in the above example, interchanging the empty array with
any and all occurences of NULL will yield the same result.

code till dawn! -mark

[#29] brian at vermonster dot com [2004-05-25 14:44:21]

Here is a fairly simple function that replaces while recursing.

<?php 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
        )
)

[#30] paska at kios dot sk [2004-03-04 02:18:50]

This emulates replace of $_REQUEST according to variable_order=GPC.
<?php function array_merge_replace($array, $newValues) { foreach ($newValues as $key => $value ) { if (is_array($value)) { if (!isset($array[$key])) { $array[$key] = array(); } $array[$key] = array_merge_replace($array[$key], $value); } else { $array[$key] = $value; } } return $array; } $_REQUEST = array_merge_replace($_REQUEST, $_GET); $_REQUEST = array_merge_replace($_REQUEST, $_POST); $_REQUEST = array_merge_replace($_REQUEST, $_COOKIE); ?>

Useful with stripping backslashes at beginning of main include file:
<?php if (get_magic_quotes_gpc() == 1) { function stripMagicSlashes($element) { if (is_array($element)) { return array_map("stripMagicSlashes", $element); } else { return stripslashes($element); } } function array_merge_replace($array, $newValues) { foreach ($newValues as $key => $value ) { if (is_array($value)) { if (!isset($array[$key])) { $array[$key] = array(); } $array[$key] = array_merge_replace($array[$key], $value); } else { $array[$key] = $value; } } return $array; } $_GET = array_map("stripMagicSlashes", $_GET); $_POST = array_map("stripMagicSlashes", $_POST); $_COOKIE = array_map("stripMagicSlashes", $_COOKIE); $_REQUEST = array_merge_replace($_REQUEST, $_GET); $_REQUEST = array_merge_replace($_REQUEST, $_POST); $_REQUEST = array_merge_replace($_REQUEST, $_COOKIE); } $GLOBALS['stripped'] = true; ?>

Based on examples from users from this site.