Re: generate series of strings

[Joke de Buhr <joke@seiken.de>]

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On Friday 09 July 2010 15:42:46 tartifola@gmail.com wrote:
> On Fri, 9 Jul 2010 15:36:00 +0200
> 
> Guillaume Brunerie <guillaume.brunerie@gmail.com> wrote:
> > 2010/7/9 <tartifola@gmail.com>
> > 
> > > Hi,
> > > is there a way to obtain from the command line a series of strings like
> > > 
> > > (1:3) (4:6) (7:9)...
> > > 
> > > always with the same increment. I'm playing with 'seq' and 'sed' but
> > > perhaps it's not the best approach.
> > > Thanks,
> > > A.
> > 
> > Hi,
> > You can use a for-loop :
> > 
> > for (( i = 0; i < 5; i++ ))
> > do
> > 
> >     echo -n "($(( 3 * i + 1 )):$(( 3 * i + 3))) "
> > 
> > done
> 
> Thanks for your help, it works perfectly. Just a curiosity, any possible
> solution without a loop for?

Actually there is a solution without loops. But it not as nice as a looping 
solution (for, while, until, ...). You can use recursive functions as a loop-
replacement. But it's not as easy as a for-loop.


## recursive function
expand() {
    (( $1 < 0 )) && return

    print -n "$(expand $(($1 - 1))) ($((3 * $1 + 1)):$((3 * $1 + 3)))" 
}

## call recursive function
expand 20

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