From: dblack@...
Date: 2007-06-07T05:54:10+09:00
Subject: Re: newbie question: deleting all of a string's contents BEFORE a certain character

Hi --

On Thu, 7 Jun 2007, superwick wrote:

> Hi,
>
> I was trying to figure out how to take a string like this: "http://
> www.youtube.com/watch?v=QMuClxuWdH8"
> and removing everything before (and including) the "=", creating a new
> string with just "QMuClxuWdH8".
>
> At first I thought I would have to do something like:
>
> url = "http://www.youtube.com/watch?v=QMuClxuWdH8"
> rev_url = url.reverse
> rev_chomped = rev_url.chomp("=")
> code = rev_chomped.reverse
>
> ...which doesn't actually work of course and is ugly anyway. I have a
> feeling I'll need to use regular expressions to do this, but I'm
> really lost when it comes to regex. How could I do something like
> this?

Try this:

   code = url.sub(/.*=/, "")

which means: replace all characters, up to and including =, with
nothing ("").  Another way is to grab a substring, matching all non-=
characters up to the end of the string:

   code = url[/[^=]+\z/]

[^=] is a character class consisting of all characters other than =.
+ means match one or more, and \z anchors the whole pattern to the end
of the string.


David

-- 
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