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

I'd do as follows using String#gsub(pattern, hash) :

string = "this is a test"
subs = {'a'=>'@','i'=>'!','s'=>'$'} # copied from @ArupRakshit
keys = subs.keys

And core code:

1.upto(keys.length).flat_map { |i| 
  keys.combination(i).flat_map { |c| string.gsub(/[#{c.join}]/, subs) } 
}

Output:

=> ["this is @ test",
 "th!s !s a test",
 "thi$ i$ a te$t",
 "th!s !s @ test",
 "thi$ i$ @ te$t",
 "th!$ !$ a te$t",
 "th!$ !$ @ te$t"]