Case insensitive in_array

Function in_array() is case sensitive - which is not always what you want. Sometimes you need to search an array, and you don’t care about the case of its elements:

function in_arrayi($needle, $haystack) {
  return in_array(strtolower($needle), array_map('strtolower', $haystack), true);
}

Example:

$array = array('a', 'B', 'cE');

in_arrayi('a', $array); // true
in_arrayi('A', $array); // true
in_arrayi('ce', $array); // true
in_arrayi('be', $array); // false