正则表达式帮助 - 需要在正则表达式中允许％

Question

i have a function which checks whether a URL contains any special characters and i want to add '%' to the allowed as i'm using %PREFIX% as a container. I'm relatively new to Regex and was wondering if someone could help me to add the % to the allowed list. The function is the below:

function specialChars($url)
{       
    if (preg_match('|^http(s)?://[a-z0-9-]+(.[a-z0-9-]+)*(:[0-9]+)?(/.*)?$|i', $url) != true)
    {
        $this->errors[] = "Please remove any special characters";           
    }       
}

Thanks in advance. Regards,

Answer 1

As http://www.regular-expressions.info/reference.html explains, [] (and its contents) defines a character class.

Since % is not a metacharacter inside of character classes (or at all) you can just place it in the character classes you want it to be allowed in, for example [a-z0-9-%]