From: Robert Klemme <shortcutter@...>
Date: 2007-06-04T21:20:34+09:00
Subject: Re: No way of looking for a regrexp match starting from a particular point in a string?

On 04.06.2007 14:06, Robert Dober wrote:
> On 6/4/07, Robert Klemme <shortcutter@googlemail.com> wrote:
>> On 04.06.2007 13:28, Robert Dober wrote:
> 
>> Robert, actually string[n..-1] is cheaper than you might assume: I
>> believe the new string shares the char buffer with the old string, so
>> you basically just get a new String object with a different offset - the
>> large bit (the char data) is not copied.
> I am afraid that this is not true anymore when the slice is passed as
> a formal parameter, the data has to be copied :(
> 
> irb(main):011:0> def change(x)
> irb(main):012:1> x << "changed"
> irb(main):013:1> end
> => nil
> irb(main):014:0> a="abcdef"
> => "abcdef"
> irb(main):015:0> change(a[1..2])
> => "bcchanged"
> irb(main):016:0> a
> => "abcdef"

Copying in this case is not caused by using the string as a parameter 
but by appending to it.

I thought this thread was about /scanning/ which is a read only 
operation.  Did I miss something?

Kind regards

	robert