Search for a key in an array, recursively

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private function find($needle, $haystack) {
    foreach ($haystack as $name => $file) {
        if ($needle == $name) {
            return $file;
        } else if(is_array($file)) { //is folder
            return $this->find($needle, $file); //file is the new haystack
        }               
    }

    return "did not find";
}

Hey, this method searches for a specific key in an associative array and returns the value associated with it. There's some problem with the recursion. Any clue?

recursion search arrays php
7 Answers

I recently came across the same issue, when dealing with Yii2 query object.

The reason your function didn't work is that the return action doesn't work here. Just pass a reference parameter to store the value, and do whatever you want afterwards.

As you can see, this is a simple PHP function doesn't rely on any library. So I think its worth to mention with all the answer listed above.

function array_search_by_key_recursive($needle, array $haystack, &$return)
{
   foreach ($haystack as $k => $v) {
      if (is_array($v)) {
        array_search_by_key_recursive($needle, $v, $return);
      } else {
        if($k === $needle){
           $return = $v;
        }
      }
   }
}

array_search_by_key_recursive($needle, array $haystack, $return);

print_r($return);
user_96556980

I just been through a similar issue and here's what worked for me:

    function searchArrayByKey($haystack, $needle, $i = 0) {
     $result = array();
     foreach($haystack as $key => $value) {
       if (is_array($value)) {
         $nextKey = searchArrayByKey($value, $needle);
         if ($nextKey) {
           return $nextKey;
         }
       }
       if (is_array($value) && array_key_exists($needle, $value)) {
         $result[$i++] = $value[$needle];
       }
     }
     if (empty($result)) {
       return false;
     } else {
       return $result;
     }
   }

This is going to return an array containing the value of all the matching keys it found in the multidimensional array. I tested this with arrays dinamically generated by an e-mail API. In the case of multiple matches, you just need to create a simple foreach loop to sort the array however you want.

I noticed the main mistake I was making was using if-ifelse conditions when I should be using if-if conditions. Any questions or criticism are very welcome, cheers!

user_139998600
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