From: Robert Klemme <bob.news@...>
Date: 2003-07-23T23:45:31+09:00
Subject: Re: String substitution without RegEx


"Andreas Schwarz" <usenet@andreas-s.net> schrieb im Newsbeitrag
news:slrnbht3o8.2jq.usenet@home.andreas-s.net...
> Robert Klemme wrote:
> >
> > "Andreas Schwarz" <usenet@andreas-s.net> schrieb im Newsbeitrag
> > news:slrnbhr0jv.d34.usenet@home.andreas-s.net...
> >> I wanted to do a simple string substitution, and was surprised to see
> >> that there isn't such a method in ruby. I can't use String::(g)sub,
> >> because the substitution mustn't be influenced by special chars or
> >> backreferences in the pattern and replacement strings. Of course I
could
> >> write functions to escape regex special chars in the pattern and
> >> backreferences in the replacement string, but this is about the
ugliest
> >> solution I can think of.
> >
> > Where's the problem?
> >
> > irb(main):004:0> "foo.bar".gsub '.', "*"
> > (irb):4: warning: string pattern instead of regexp; metacharacters no
> > longer eff
> > ective
> > "foo*bar"
>
> irb(main):001:0> "foo.bar".gsub '.', "*"
> => "*******"

Ah, then it's a ruby version thingy.  I used 1.7.3.  Which one do you
have?

> > Or you use Regexp.escape as others already have pointed out:
> >
> > irb(main):017:0* "foo.bar".gsub( /#{Regexp.escape(".")}/, "*" )
> > "foo*bar"
>
> irb(main):007:0> "foo.bar".gsub( /#{Regexp.escape(".")}/, "\\1")
> => "foobar"

Why do you use \1 if you want to replace a fixed string?  Or do you want
to insert \1?  Then you shoul've done

"foo.bar".gsub( /#{Regexp.escape(".")}/, Regexp.escape("\\1") )

Cheers

    robert