A function to apply the functionality of filter_input() to arbitrary arrays

filter_array.php

/**
 * filter_input() for arbitrary arrays.
 * 
 * @param array $data The array to fetch the data from.
 * @param string $name The array key of interest.
 * @param integer $filter A filter constant
 * @param integer|array $options Either a filter flag or an array denoting 
 *          flags and/or options.
 * @return mixed The requested value or FALSE or NULL.
 */
function filter_array(array $data, $name, $filter = FILTER_DEFAULT, $options = NULL)
{
    if (!is_int($filter)) {
        throw new UnexpectedValueException('Filter must be a filter constant.');
    }
    $name = (string) $name;

    if (is_null($options)) {
        $options = $filter;
    }
    elseif (is_int($options)) {
        $options |= $filter;
    }
    elseif (is_array($options)) {
        $options['filter'] = $filter;
        $options = array_intersect_key($options, array_flip(array('filter', 'flags', 'options')));
    }

    $out = filter_var_array($data, [$name => $options], true);
    return $out[$name];
}