From: Michael Morin <uzimonkey@...>
Date: 2008-08-16T19:42:30+09:00
Subject: Re: Idiom of removing a particular character from a String?

Lorenzo E. Danielsson wrote:
> Hi all,
> 
> Is there any particular idiom for removing a particular character from a
> string *by index* and returning the resulting string? The following
> makes my old eyes sore:
> 
> rem = str.clone
> rem[i] = ""
> rem
> 
> as does this:
> 
> rem = str.scan(/./)
> rem.delete_at(i)
> rem.to_s
> 
> It seems there should be some more idiomatic way to do this, something
> like str.annihilate_char_at_index_possibly_without_a_bang(i), read as
> String#delete_at(i) and String#delete_at!(i). Of course these methods
> don't exist, and "".methods doesn't turn up anything interesting. So
> what is a *decent* way of performing this? 
> 
> Lorenzo
> 
> 

There have been some good solutions posted already.  However, I don't 
think I'd want to be repeating them many times (or at all) in my code. 
Whichever solution you use, it's probably best to hide it away in the 
String class somewhere, else your code will suddenly start looking... 
perl-like.

This seems sensible to me.  If you're on 1.8.7 or 1.9 (I am not), you 
can also use the tap method.

class String
   def rem(idx)
     c = clone
     c[idx..idx] = ""
     c
   end

   def rem!(idx)
     self[idx..idx] = ""
     self
   end
end

If you're on 1.8.7, 1.9 or feel like implementing it yourself, you can 
use the tap method.  Using the tap method seems cleaner.

unless Object.methods.include? "tap"
   class Object
     def tap
       yield self
       self
     end
   end
end

class String
   def rem(idx)
     clone.tap {|t| t[idx..idx] = "" }
   end

   def rem!(idx)
     tap {|t| t[idx..idx] = "" }
   end
end

-- 
Michael Morin
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