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arrays – php recursive merge

Posted by: admin July 12, 2020 Leave a comment

Questions:

I need to merge some arrays in some different way and I use array_merge_recursive.
However there is something that I need to change and I don’t know how.
Here is quote from php.net

If, however, the arrays have the same numeric key, the later value
will not overwrite the original value, but will be appended.

I want this value, NOT to be appended, I want not to append exact values in the new array.Hope you’ve understood this.

Example:

$array = array(
   'some'  => array(
       'other'    => 'key',
   ),
);

$array2 = array();
$array2['some']['other'] = 'key2';

If I use array_merge_recursive It will result this:

Array (
    [some] => Array
        (
            [other] => Array
                (
                    [0] => key
                    [1] => key2
                )
        ) )

I want if it matches the same result, not to append it.Yes I know, you would say, then use array_merge, but it doesn’t work well, too.
If I use this:

$array = array(
   'some'  => array(
       'other'    => 'key',
   ),
);

$array2 = array();
$array2['some']['other2'] = 'key2';

print_r(array_merge($array, $array2));

It will remove $array[some][other] from the list and leave only $array[some][other2].I don’t know which is better, since no one makes it better.

How to&Answers:

try this

<?php
function mymerge(&$a,$b){ //$a will be result. $a will be edited. It's to avoid a lot of copying in recursion
    foreach($b as $child=>$value){
        if(isset($a[$child])){ 
            if(is_array($a[$child]) && is_array($value)){ //merge if they are both arrays
                mymerge($a[$child],$value);
            }
            //else ignore, you can add your own logic, i.e when 1 of them is array
        }
        else
            $a[$child]=$value; //add if not exists
    }

    //return $a;
}

Answer:

For PHP >= 5.3 just use array_replace_recursive

Answer:

I wrote my merge class for it:

<?php

class ArrayMerge
{

    /**
     * @param array $a
     * @param array $b
     *
     * @return array
     */
    public function merge ( $a, $b ) {
        foreach ( $b as $k => $v ) {
            if ( is_array( $v ) ) {
                if ( isset( $a[ $k ] ) ) {
                    if ( $this->isDeep( $v ) ) {
                        $a[ $k ] = $this->merge( $a[ $k ], $v );
                    } else {
                        $a[ $k ] = array_merge( $a[ $k ], $v );
                    }
                } else {
                    $a[ $k ] = $v;
                }
            } else {
                $a[ $k ] = $v;
            }
        }
        return $a;
    }

    /**
     * @param array $array
     *
     * @return bool
     */
    private function isDeep ( $array ) {
        foreach ( $array as $elm ) {
            if ( is_array( $elm ) ) {
                return TRUE;
            }
        }
        return FALSE;
    }

}

Answer:

I started from RiaD’s version and added object handling. Need testing and feedback

function recursiveMerge(&$a,$b){ //$a will be result. $a will be edited. It's to avoid a lot of copying in recursion
        if(is_array($b) || is_object($b)){
            foreach($b as $child=>$value){
                if(is_array($a)){
                    if(isset($a[$child]))
                        recursiveMerge($a[$child],$value);
                    else
                        $a[$child]=$value;
                }
                elseif(is_object($a)){
                    if(isset($a->{$child}))
                        recursiveMerge($a->{$child},$value);
                    else
                        $a->{$child}=$value;
                }
            }
        }
        else
            $a=$b;
    }

Answer:

An other alternative, the array_merge_deep from drupal:

function array_merge_deep($arrays) {
  $result = array();
  foreach ($arrays as $array) {
    foreach ($array as $key => $value) {
      // Renumber integer keys as array_merge_recursive() does. Note that PHP
      // automatically converts array keys that are integer strings (e.g., '1')
      // to integers.
      if (is_integer($key)) {
        $result[] = $value;
      }
      // Recurse when both values are arrays.
      elseif (isset($result[$key]) && is_array($result[$key]) && is_array($value)) {
        $result[$key] = array_merge_deep(array($result[$key], $value));
      }
      // Otherwise, use the latter value, overriding any previous value.
      else {
        $result[$key] = $value;
      }
    }
  }
  return $result;
}