Alternation operator inside square brackets does not work

I'm creating a javascript regex to match queries in a search engine string. I am having a problem with alternation. I have the following regex:

.*baidu.com.*[/?].*wd{1}=

I want to be able to match strings that have the string 'word' or 'qw' in addition to 'wd', but everything I try is unsuccessful. I thought I would be able to do something like the following:

.*baidu.com.*[/?].*[wd|word|qw]{1}=

but it does not seem to work.

2012-04-04 22:03
by well actually

[] creates a character class, use (wd|word|qw) instead. Also get rid of that {1}, it's useless - NullUserException 2012-04-04 22:04

A little more context on what you are trying to accomplish would help us to help you a lot more : - Code Jockey 2012-04-04 22:26

replace [wd|word|qw] with (wd|word|qw).

[] denotes character sets, () denotes logical groupings.

2012-04-04 22:07
by bhamlin

+1, but... going one step further, you could add "replace (wd|word|qw) with qw|w(?:or)?d - zx81 2014-06-07 11:26

Your expression:

.*baidu.com.*[/?].*[wd|word|qw]{1}=

does need a few changes, including [wd|word|qw] to (wd|word|qw) and getting rid of the redundant {1}, like so:

.*baidu.com.*[/?].*(wd|word|qw)=

But you also need to understand that the first part of your expression (.*baidu.com.*[/?].*) will match baidu.com hello what spelling/handle????????? or hbaidu-com/ or even something like lkas----jhdf lkja$@@!3hdsfbaidugcomlaksjhdf.[($?lakshf, because the dot (.) matches any character except newlines... to match a literal dot, you have to escape it with a backslash (like \.)

There are several approaches you could take to match things in a URL, but we could help you more if you tell us what you are trying to do or accomplish - perhaps regex is not the best solution or (EDIT) only part of the best solution?

2012-04-04 22:22
by Code Jockey