Feature #9108
Updated by ko1 (Koichi Sasada) over 9 years ago
=begin Hi, I seem to regularly have the requirement to work on a sub-set of key/value pairs within a hash. Ruby doesn't seem to provide a concise means of selecting a sub-set of keys from a hash. To give an example of what I mean, including how I currently achieve this: ```ruby sounds = {dog: 'woof', cat: 'meow', mouse: 'squeak', horse: 'nay', cow: 'moo'} domestic_sounds = sounds.select { |k,v| [:dog, :cat].include? k } #=> {dog: 'woof', cat: 'meow'} ``` I think a more concise and graceful solution to this would be to allow the Hash#[] method to take multiple arguments, returning a sub-hash, e.g. ```ruby domestic_sounds = sounds[:dog, :cat] #=> {dog: 'woof', cat: 'meow'} ``` I had a requirement in the current project I'm working on to concatenate two values in a hash. If this proposed feature existed, I could of just done this... ```ruby sounds[:dog, :cat].values.join #=> 'woofmeow' ``` You could do something similar for the setter also... ```ruby sounds[:monkey, :bat] = 'screech' sounds #=> {dog: 'woof', cat: 'meow', mouse: 'squeak', horse: 'nay', cow: 'moo', monkey: 'screech', bat: 'screech'} ``` Concise, convenient and readable. Thoughts? =end