From: Sebastian Hungerecker <sepp2k@...>
Date: 2007-07-21T04:16:44+09:00
Subject: Re: Is there a replacement for sub?

Michael W. Ryder wrote:
> Martin DeMello wrote:

> > a = "a b c d e f"
> > b = a
> > a = a.sub(" ", "") # => a is now "ab c d e f", b is still "a b c d e f"
>
> Wrong. 

Nope.

> Unless you use b = a.dup b will be the same as a as it is 
> pointing to the same object. 

Yes.

> The result of the sub operation will 
> change b as well as a.

No, sub won't change the actual string - that's what sub! would do. It will
create a new string which will be assigned to a, at which point a and b won't
be pointing at the same object anymore.


> I guess my problem is that the sub operations return a nil if they don't
> make a change rather than the unchanged object.

They don't. sub! (the destructive method) will return nil, sub will return the 
unchanged object.


> Maybe I need to write a version of sub or a method for 
> it that returns the string regardless of whether it was changed or not.

sub does that already.


-- 
NP: Milhaven - Clean Room
Ist so, weil ist so
Bleibt so, weil war so