PHP regex a-Z 0-9 () and []

Question

I'm new to regex, so I've done a bit research. My filter should only allow:

I've found this regex:

"/^[a-zA-Z0-9]+$/"

I edited it to allow ()

"/^[a-zA-Z0-9()]+$/"

But how to make the regex allowing [] too? Seems like [] need to be escaped somehow.

Have you read the documentation of [Perl-Compatible Regular Expressions](http://php.net/manual/en/pcre.pattern.php) in PHP? — axiac, Mar 19 '18 at 06:06

score 1 · Answer 1 · answered Mar 19 '18 at 05:52

1

The character \ is the escape character in regex. Try this:

"/^[a-zA-Z0-9()\[\]]+$/"

answered Mar 19 '18 at 05:52

e_i_pi

score 1 · Answer 2 · answered Mar 19 '18 at 06:01

1

You do not need to escape the square brackets if you put them first, like so:

^[][a-zA-Z0-9()]+$

See a demo on regex101.com.
Please also note that a-Z is not the same as a-zA-Z, see the famous answer from @Wiktor here for more details.

answered Mar 19 '18 at 06:01

Jan

2 Answers2