简单的正则表达式以匹配某些字符并排除其他字符

Question

I need a regex for preg_match to accept all alphanumeric characters except l , L , v , V , 0 , 2 .

I've tried

^[a-zA-Z0-9][^lLvV02]*$

It works good excluding lLvV02 but it also accept other characters like SPACE,ù,@,#, etc...

How should I change it?

Answer 1

You may use

^(?:(?![lLvV02])[a-zA-Z0-9])*$

Details

• ^ - start of string
• (?: - start of a non-capturing group
  • (?![lLvV02])[a-zA-Z0-9] - an alnum char that is not one of the chars inside the character class residing inside a negative lookahead
• )* - end of the non-capturing group, 0 or more repetitions
• $ - end of string

See the Regulex graph :

Answer 2

I know you asked for a Regex, but you can test for alphanumeric first and only if that passes check that the others are NOT present:

if(ctype_alnum($string) && !preg_match('/[lLvV02]/', $string)) {
    //pass
} else {
    //fail
}

Or possibly substitute preg_match('/^[^lLvV02]+$/', $string) .

Answer 3

Easiest would probably be: ^[a-km-uw-zA-KM-UW-Z13-9]*$ . I'm not saying that it's pretty but it does what it's supposed to.