Test if string is URL encoded in PHP

Question

How can I test if a string is URL encoded?

Which of the following approaches is better?

• Search the string for characters which would be encoded, which

Answer 1

well, the term "url encoded" is a bit vague, perhaps simple regex check will do the trick

$is_encoded = preg_match('~%[0-9A-F]{2}~i', $string);