Get Array Values Recursively with PHP

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I've been helping to write a WordPress plugin (I'm not ready to share it yet) and one of the tasks required is validating an array of user-selected values against a list of known valid values.  The known valid array is actually a key=>value array so unfortunately array_values wont help get the simple list I'd like.

Instead a more advanced custom function was needed:

// http://php.net/manual/en/function.array-values.php
function array_values_recursive($array) {
  $flat = array();

  foreach($array as $value) {
    if (is_array($value)) {
        $flat = array_merge($flat, array_values_recursive($value));
    }
    else {
        $flat[] = $value;
    }
  }
  return $flat;
}

This recursive function dives into arrays, even key=>value arrays, to retrieve the final list of values.  Thank you PHP.net!

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Discussion

    • Jeremy

      Although if you’re going to call iterator_to_array() I think you’ve defeated your stated purpose for using iterators.

    • Rafael

      I just love this blog, I always get to know something new. I didn’t know about this. Very useful!

  1. zdenko
    function flatten_array($arg) {
      return is_array($arg) ? array_reduce($arg, function ($c, $a) { return array_merge($c, flatten_array($a)); },[]) : [$arg];
    }
    

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