Thanks William and Stefan,

your right, gsub! is a better way to do what I want. But your solution
doesn't work, either. I think ruby has a problem by invoking gets.chomp
(by the way Stefan, it made for me no difference to use $stdin.gets
instead of gets )-: in a block. I hope you know a workaround (I tried
to write ..do..end instead of {}, but it doesn't changed anything in
the behaviour of my program)

thanks,
naPOLeon

William James wrote:
> naPOLeon wrote:
> > Hello,
> > I'm a just beginner to ruby and impressed by the possibility to test
> > code in irb. Today I wrote a line of code in irb and it behaved as I
> > expected. But when I inserted it in my program and executed with ruby,
> > the code-block didn't worke. Maybe you could tell me why.
> >
> > The line
> >
> > a.scan(reg_exp).each {|w| print "#{w.to_s}: "
>
> w is already a string.
>
> >             ; a.sub!(reg_exp,
> > gets.chomp)}
>
> To me, it doesn't make sense to change the string
> while you are scanning it.
>
> Try this:
>
> a = "foo <trew> bar <tich>"
> reg_exp = /<\w*>/
> a.gsub!(reg_exp) { |w| print "#{w}: "; gets.chomp }
>
> p a
>
>
> >
> > It asked me in irb depending on the size of 'a' for some input and
> > replaced a part (I used the Regular Expression /<\w*>/) of the string
> > 'a' with my input.
> > But if I use this line in a program, the part 'gets.chomp' seems to be
> > ignored. The result is no change on String 'a'.
> >
> > I've no explanation for this strange behaviour, I hope you can give me
> > a hint. Maybe the whole line is rubbish and there is a lot better way
> > to do the job?
> > 
> > Thanks,
> > naPOLeon