In Ruby, is there an Array method that combines 'select' and 'map'?

Question

I have a Ruby array containing some string values. I need to:

1. Find all elements that match some predicate
2. Run the matching elements through a transfo

Answer 1

I usually use map and compact together along with my selection criteria as a postfix if. compact gets rid of the nils.

jruby-1.5.0 > [1,1,1,2,3,4].map{|n| n*3 if n==1}    
 => [3, 3, 3, nil, nil, nil] 


jruby-1.5.0 > [1,1,1,2,3,4].map{|n| n*3 if n==1}.compact
 => [3, 3, 3]