正则表达式可以匹配字母数字字符或连字符以外的任何内容

Question

I am trying to allow users to register a username that contains only alphabet letters (of any language), numbers, or hyphens in it. I'm trying to check if a username breaks this rule.

So far this is working to find out if a username does not contain only alphanumeric characters:

REFindNoCase('^[[:alnum:]]', ARGUMENTS.Username)

Which is fine because if I get back a found result then I know its an invalid username format with special characters in it. But I also want to allow hyphens through. How could I express in regex like (pseudo-code follows):

REFindNoCase('^[[:alnum:]\-]', ARGUMENTS.Username)

I can only use Perl compatible Regex because I am using ColdFusion which uses that standard mostly.

Answer 1

First of all, you're wrong about REFindNoCase('^[[:alnum:]]', ARGUMENTS.Username) being fine. It checks if the first character is alphnumeric.

$ for q in Abcdef Abc123 Abc-123 Abc/123 ; do
   if echo "$q" | grep -qP '^[[:alnum:]]'
   then echo "$q: match"
   else echo "$q: no match"
   fi
done
Abcdef: match
Abc123: match
Abc-123: match
Abc/123: match

( grep -P uses PCRE too.)

To look for character that is not an alnum character, you'd use

[^[:alnum:]]

As seen here:

$ for q in Abcdef Abc123 Abc-123 Abc/123 ; do
   if echo "$q" | grep -qP '[^[:alnum:]]'
   then echo "$q: match"
   else echo "$q: no match"
   fi
done
Abcdef: no match
Abc123: no match
Abc-123: match
Abc/123: match

To look for character that are neither an alnum character nor "-", you'd use

[^[:alnum:]-]

As seen here:

$ for q in Abcdef Abc123 Abc-123 Abc/123 ; do
   if echo "$q" | grep -qP '[^[:alnum:]-]'
   then echo "$q: match"
   else echo "$q: no match"
   fi
done
Abcdef: no match
Abc123: no match
Abc-123: no match
Abc/123: match

By the way, REFind would work just as a well as REFindNoCase since alnum includes both uppercase and lowercase letters, so might as well use REFind .

Answer 2

Update: I looked at this question RegEx: \\w - "_" + "-" in UTF-8

Final solution after trial and error (the negation had to be inside the opening bracket):

REFind('[^[:alnum:]-]', ARGUMENTS.Username)