ansaurus

Question

Answer 1

+2 A:

(?:www)?

should match www or nothing.

gameover 2010-01-10 18:29:37

You mean /www|nothing/ :p

KennyTM 2010-01-10 18:35:52

What does the "?:" before "www" do?

stiank81 2010-01-10 18:38:17

It is for grouping *only*

gameover 2010-01-10 18:40:26

`(abc)` is capturing, `(?:abc)` is grouping without capturing. See http://www.regular-expressions.info/brackets.html

KennyTM 2010-01-10 18:40:35

Thx for clearing that up :-)

stiank81 2010-01-10 18:43:10

One thing to note though, is it still will not match localhost.com, you'll need to ignore the dot afterwards also.

William 2010-01-10 18:58:28

This will match www anywhere in the string, such as examplewww.com

BlueRaja - Danny Pflughoeft 2010-01-10 19:07:47

Answer 2

A:

If I understand your question correctly, you need to use a lookahead, like this:

/^www(?=\.localhost.com)/

This will match www if and only if it's followed by .localhost.com.

If that's not what you're trying to do, please clarify.

SLaks 2010-01-10 18:30:57

This won’t match anything because you can’t match a `.localhost.com` after the end of the string.

Gumbo 2010-01-10 18:39:14

@Gumbo: Fixed; thanks.

SLaks 2010-01-10 18:41:42

Answer 3

A:

www.+? It matches all string that has prefix as www

Daniel 2010-01-10 18:31:57

Answer 4

A:

/^www/ alows you to check if subjects starts with www.

hsz 2010-01-10 18:33:22

regex match www or nothing