I made these two functions to extend the default String object:

class String
	def rtrim(character)

		if self[-1, 1] == character.to_s
			self[0, self.length - 1]
		end
		return self
	end

	def ltrim(character)
		if self[0, 1] == character.to_s
			self[1, self.length]
		end
		return self
	end
end

Are they ok? I mean, aren't there any default Ruby functions I am
copying? I looked on google for functions that did the same as above
functions, but I couldn't find any for Ruby.

Thanks in advance!

Pfff... Sorry for the second post. I couldn't find the first one on
Google groups.
I tried changing the self object. But I wasn't allowed to do it. I got
an error message when I did that:
"Can't change the value of self"

So I changed it to:

class String
	def rtrim(character)

		ret = self
		if self[-1, 1] == character.to_s
			ret = self[0, self.length - 1]
		end
		return ret
	end

	def ltrim(character)
		if self[0, 1] == character.to_s
			ret = self[1, self.length]
		end
		return ret
	end
end

This works. But I would rather see the first object changed. Is this
possible?

Ow yeah. rstrip and lstrip only strip spaces (and maybe line-endings).
I also want to use it for other characters.

On 7/25/07, LeonB <leon@tim-online.nl> wrote:
> Pfff... Sorry for the second post. I couldn't find the first one on
> Google groups.
> I tried changing the self object. But I wasn't allowed to do it. I got
> an error message when I did that:
> "Can't change the value of self"
>
> So I changed it to:
>
> class String
>         def rtrim(character)
>
>                 ret = self
>                 if self[-1, 1] == character.to_s
>                         ret = self[0, self.length - 1]
>                 end
>                 return ret
>         end
>
>         def ltrim(character)
>                 if self[0, 1] == character.to_s
>                         ret = self[1, self.length]
>                 end
>                 return ret
>         end
> end
>
> This works. But I would rather see the first object changed. Is this
> possible?

Leon, look at String#slice!

Todd

Leon Bogaert wrote:
> This works. But I would rather see the first object changed. Is this
> possible?

I would argue that ltrim and rtrim should not remove one character, but
a sequence of the given character.  The following code probably does
not meet all ruby conventions, but it does what you request and it does
reserve ! for its intended purpose.

class String
  def rtrim!(character)
    n = 0
    while (self[-(n+1), 1] == character.to_s)
      n +=1
    end
    self.slice!(self.length - n,n) if n > 0
  end

  def ltrim!(character)
    n = 0
    while (self[n, 1] == character.to_s)
      n += 1
    end
    self.slice!(0 , n) if n > 0
  end
end

s = "aaaaaabacbccccc"
p s
s.rtrim!("c")
p s
s.ltrim!("b")
p s
s.ltrim!("a")
p s

Ian
-- 
Posted via http://www.ruby-forum.com/.

On 7/26/07, Ian Whitlock <iw1junk@comcast.net> wrote:
> Leon Bogaert wrote:
> > This works. But I would rather see the first object changed. Is this
> > possible?
>
> I would argue that ltrim and rtrim should not remove one character, but
> a sequence of the given character.  The following code probably does
> not meet all ruby conventions, but it does what you request and it does
> reserve ! for its intended purpose.

Since we got the power of regex/gsub, let's use it :)

class String
  def rtrim(char)
    dump.rtrim!(char)
  end

  def rtrim!(char)
    gsub!(/#{Regexp.escape(char)}+$/, '')
  end

  def ltrim(char)
    dump.ltrim!(char)
  end

  def ltrim!(char)
    gsub!(/^#{Regexp.escape(char)}+/, '')
  end
end

s = "aaaaaabacbccccc"
p s
s.rtrim!("c")
p s
s.ltrim!("b")
p s
s.ltrim!("a")
p s

Michael Fellinger wrote:

> Since we got the power of regex/gsub, let's use it :)

Michael,

Thanks.  I agree that in practice your code is better.
I am a newbie who does not yet feel comfortable with
regular expressions, but I see what you have done.

Ian
-- 
Posted via http://www.ruby-forum.com/.