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  1. f = -> s {[''].product(*s.chars.map {|c| [c, c.upcase]}).map(&:join)}
  2. p %W(#{} a ab).map {|s| [s, f.(s)]}
  3.  
Success #stdin #stdout 0s 28216KB
comments (?)
stdin 
Standard input is empty
stdout 
[["", [""]], ["a", ["a", "A"]], ["ab", ["ab", "aB", "Ab", "AB"]]]
https://ideone.com/lGQ1lX
language:
Ruby (ruby 2.5.5)
created:
6 years ago
visibility:
secret

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