CODEWITHSUNDEEP
phpnullusort
Viktor
Viktor

Reputation: 547

PHP USort gives null warning when array is empty

    function sort_multi_array($array, $key)
{
  if (is_null($array)) return 0;
  $keys = array();
  for ($i=1;$i<func_num_args();$i++) {
    $keys[$i-1] = func_get_arg($i);
  }

  // create a custom search function to pass to usort
  $func = function ($a, $b) use ($keys) {
    for ($i=0;$i<count($keys);$i++) {
      if ($a[$keys[$i]] != $b[$keys[$i]]) {
        return ($a[$keys[$i]] > $b[$keys[$i]]) ? -1 : 1;
      }
    }
    return 0;
  };

  usort($array, $func);

  return $array;
}

I'm building a simple search query however when it reaches the end i.e. no more entries in Warning: usort() expects parameter 1 to be array, null given in

How can I test to see if the array is empty and simply return a null result before it reaches the usort line?

thank you!

Upvotes: 0

Views: 1523

Answers (2)

Sougata Bose
Sougata Bose

Reputation: 31749

Add a check for empty data - 

if (!empty($array)) {
   // process data
}

Upvotes: 0

pavel
pavel

Reputation: 27072

Check before using usort if the $array is null or not.

if ($array !== NULL) {
    usort($array, $func);
}

Upvotes: 2

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