From: Mark Slagell <ms@...>
Date: 2001-10-11T09:11:21+09:00
Subject: [ruby-talk:22416] Re: list comprehensions alike Python ???

Paul Prescod wrote:
> 
> Robert Feldt wrote:
> >
> >...
> > $ irb
> > irb(main):001:0> (1..11).map {|v| v*v}
> > [1, 4, 9, 16, 25, 36, 49, 64, 81, 100, 121]
> >
> > Short enough for my taste... (but maybe there are some benefits to the
> > Python way? I don't know any Python.)
> 
> Out of curiousity, what would the Ruby for this look like:
> 
> >>> arr = [x*x for x in range(0,10) if x%2==0]
> >>> arr
> [0, 4, 16, 36, 64]
> 
> A combination of filter and map?
> 
>  Paul Prescod

A couple of ways spring to mind.

 (0..10).select{|x| x%2==0}.map{|x| x*x}

or

 (0..10).map{|x| x*x if x%2==0}.compact