From: Phlip <phlip2005@...>
Date: 2008-11-13T22:27:20+09:00
Subject: Re: '#' characters are breaking my regexp

>>> string = "abc#def"
> => "abc#def"
>>> /#{string}/
> => abc
>>> string = "abc\#def"

"abc\\#def"

When you mash like /#{string}/, the inserted item is not treated as a 
literal string, but as a fragment of Regexp notation. So either first call 
Regexp.escape(string) on it, or make it a valid regexp.

Next, "" might interpret \# as an escape in string notation, so escape 
_that_ with \\#.

And I always use '' unless I need the special powers of a "". So 'abc\#def' 
will work, because '' refrains from escaping anything that it doesn't need 
to.