asked on

Non alphanumeric regex - easy!

I have a simple regex question, I just want to know if a string contains any characters other than a-z, 0-9 and - and _

I tried this:

      if (preg_match("/[^A-Z0-9_-]/", $_REQUEST['name'])) {
            echo "here";
      }

but that is not right. What am I doing wrong?

Diablo84

hi thepadders,

try this pattern: "/^[A-Z0-9_-]+$/"

if (preg_match("/^[A-Z0-9_-]+$/", $_REQUEST['name'])) {
echo "here";
}

bear in mind it is case sensitive

SOLUTION

Diablo84

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Diablo84

This page may be useful to you: http://us2.php.net/manual/en/reference.pcre.pattern.syntax.php

Pattern syntax. Note in the above i have used:

\w = any "word" character
\d = any decimal digit

ASKER CERTIFIED SOLUTION

Zvonko

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Diablo84

good point about \w, it of course covers _ too

although your pattern does not match with a test, so perhaps the pattern: "/^[\w\-]+$/"

eeBlueShadow

Zvonko,

a '-' placed at the start or end of a character class [square braces] does not need escaping, only when it is surrounded by other characters :)

But that's as good as it gets

_Blue

mces

Diablo, what you recommend, matches to strings that ALL THEIR CHARACTERS are something other than alphanumberic and dash.
The pattern he looks for is /[^\w-]/. Just that.

thepadders

ASKER

Thank you everyone, mces had the best answer is

if (preg_match("/[^\w\-]/", $_REQUEST['name'])) {
echo "here";
}

I have split the points as it was a progression to that answer. Thanks everyone.

Zvonko

You are welcome.