Recursive replacement for in_array() function

array_search_recursive.php

<?php

# Recursive replacement for in_array() function
function array_search_recursive($needle, $haystack) {
  
  # Validate data types
  if (is_array($needle) || !is_array($haystack)) {
    return null;
  }

  # Check if in_array() will suffice
  if (in_array($needle, $haystack)) {
    return true;
  }

  # Enter recursion...
  foreach ($haystack as $element) {
    if (!is_array($element)) {
      return null;
    }
    if (array_search_recursive($needle, $element)) {
      return true;
    }
  }
  return false;
}