From: "Guy N. Hurst" <gnhurst@...>
Date: 2000-12-13T04:31:38+09:00
Subject: [ruby-talk:7099] Re: Rubyize this method

"Morris, Chris" wrote:
> 
> I ported this from Delphi ... I'd hoped there was a built in string method
> to do what this does, but haven't been able to skim it out of the book yet.
> I assume it's probably staring me in the face...
> 
>   def lopOff(s, substr)
>     return s[(s.index(substr) + substr.length)..s.length]
>   end
> 
> lopOff("test this", "tes")  => "t this"
>

If you insist on a global method, I would do it this way:

irb(main):008:0> def lopOff(s,substr)
irb(main):009:1> return s.sub(/^#{substr}/,"")
irb(main):010:1> end
nil
irb(main):011:0> s="test this"
"test this"
irb(main):012:0> lopOff(s,"tes")
"t this"

Otherwise, I would prefer to add it as a method
of class String like this:

irb(main):013:0> class String
irb(main):014:1> def lopOff(substr)
irb(main):015:2> self.sub!(/^#{substr}/,"")
irb(main):016:2> end
irb(main):017:1> end
nil
irb(main):018:0> "test this".lopOff("tes")
"t this" 
irb(main):019:0> s.lopOff("tes")
"t this"
irb(main):020:0> s
"t this"

If you do not wish for 's' to be permanently changed,
remove the '!' after 'sub' in the definition; it will
then do its work on a copy of itself.



Guy N. Hurst
 

-- 
HurstLinks Web Development    http://www.hurstlinks.com/
Norfolk, VA - (757)623-9688
PHP/MySQL - Ruby/Perl - HTML/Javascript