仅允许使用preg_match的几个字符

Question

I want to use preg_match to allow only few characters, more exactly, I want to allow only these characters: az AZ 0-9 . , ( ) @ # ! ?

How can I do that with preg_replace, to check if text contains more than these characters or not?

Answer 1

In order to test if your sting contains invalid characters, you could do:

if ( preg_match('/[^a-zA-Z0-9.,()@#!?]/', $string) )
    echo 'At least ONE invalid character found!';

I'm not sure I well understand what you want, but here are some regex that you can use:

if ( preg_match('/^[^a-zA-Z0-9.,()@#!?]+$/', $string) )
    echo 'All characters are invalid!';

if ( preg_match('/^[a-zA-Z0-9.,()@#!?]+$/', $string) )
    echo 'All characters are valid!';

Answer 2

如果要删除字符串中除指示字符外的所有字符，可以使用：

$sanitized = preg_replace('/[^a-zA-Z0-9\.\,\(\)@#!?]/', '', $string);