Topic: [SOLVED] Only allow A-Z, 0-9, dashes, underscores, and spaces

[pugboy]

I have tried looking at these expressions, and I really don't know how anyone can understand them. Amazing that people can

I need to allow only A-Z (upper or lowercase) 0-9 and spaces, dashes, and underscores...

I will be replacing the spaces with dashes however, so that this string is URL friendly and more pleasing to the eye than 'index.php?id=1384'... EDIT: IE is behaving oddly... SUbmitted on accident and I can barely edit... Can anyone point me to a premade expression or help me find a good beginner tutorial on these?

[corbin]

Google "regular expressions tutorial" or there's a sticky around here some where.


Anyway:


if(preg_match('/^[\dA-Za-z _-]+$/', $str)) {
    //valid
}


That would be one or more of them.  If you want any amount, change the + to a *.

[DarkWater]

Or, to shorten it up a bit:

Code: [Select]

<?php
if (preg_match('/^[\w-]+$/', $str) {
    //good
}
else {
    //not so good
}


[corbin]

Doesn't \w match all kinds of whitespace?  Like tabs?  (And new lines in multiline mode)

[DarkWater]

Doesn't \w match all kinds of whitespace?  Like tabs?  (And new lines in multiline mode)

That's \s.  \w is "word characters", or [A-Za-z0-9_].

[corbin]

Ahhhhhhhh.....  That's why I don't use character classes.  Screw memorization, although \s isn't hard to remember since space.

[DarkWater]

Ahhhhhhhh.....  That's why I don't use character classes.  Screw memorization, although \s isn't hard to remember since space.

\d, digit
\w, word
\s, space
=P I think they tried to make it pretty easy to remember.

[corbin]

Yeah, I usually use \d just because it's easier than 0-9.  I usually remember \s too.  Not sure why I was thinking the word class included space.