All possible combinations of selected character substitution in a string in ruby

Question

I was wondering if there is a simple way to do every combination of selected character substitutions in ruby in a simple way.

An example:

    string          


        

Answer 1

string = "this is a test"
subs = ['a'=>'@','i'=>'!','s'=>'$']

subs = subs.first.map(&:to_a)
1.upto(subs.length).each do |n|
  subs.combination(n).each do |a|
    p a.each_with_object(string.dup){|pair, s| s.gsub!(*pair)}
  end
end