From: Keith Johnston <keith@...>
Date: 2008-10-01T21:58:05+09:00
Subject: Re: String delete method help

Hi,

Yes, that helped. I was able to achieve what I thought the delete
function was doing by using String#sub! with a regular expression to
remove any charaters between "http" and "com".

string = "http://groups.google.com/group/ruby-talk-google/".sub!(/
http.*com/, "")


Thanks,

On Oct 1, 12:58 pm, Stefano Crocco <stefano.cro...@alice.it> wrote:
> Alle Wednesday 01 October 2008, Keith Johnston ha scritto:
>
>
>
> > Hi,
>
> > I have a string which hold a URL. I'm trying to use the string .delete
> > method to remove the domain from the url but it isn't working as I
> > thought it should from the docs.
>
> > For example:
>
> > string = "http://groups.google.com/group/ruby-talk-google/"
>
> > I want to remove the "http://groups.google.com" part of the string, so
> > I tried:
>
> > string.delete('http', 'com')
>
> > thinking this would delete everything between 'http' and 'com' but all
> > I get is the entire string without any changes and with no errors.
>
> > I'm probably misunderstanding how the delete function works - can
> > someone explain?
>
> > Thanks,
>
> There are two reasons for which your code doesn't do what you want:
> * String#delete is a non-destructive method, that is it doesn't change its  
> receiver but creates a new string which is a copy of the receiver, modifies it
> and returns it:
>
> str = "abc"
> str1 = str.delete 'a'
> puts str
> => "abc"
> puts str1
> => "bc"
>
> If you want to modify the string in place, use String#delete!, instead
>
> * String#delete removes from the string the characters which are the
> intersection between its arguments. This means that a) it works character-
> wise, so calling str.delete("abc") will delete all 'a', all 'b' and all 'c',
> not just all instances of the substring 'abc'; b) in your case, the two
> strings you pass to delete have no characters in common, so none will be
> removed.
>
> One way to do what you want is to use sub!:
>
> string = "http://groups.google.com/group/ruby-talk-google/"
> string.sub!("http://groups.google.com", '')
>
> I hope this helps
>
> Stefano