Return single :key from nested hash in ruby

问题

From psd.rb gem by LayerVault, I get a hash that contains all the layers and groups of the psd in nested hashes. Here is a gist of the hash. I want to retrieve a certain key from that hash. Is there a way to do this and store those keys values in an array?

回答1:

def values(hsh, key)
  return [] if !hsh.kind_of? Hash
  v = hsh[key] ? [hsh[key]] : []
  hsh.values.select{|i| i.kind_of? Hash or i.kind_of? Array}.each do |val|
    if val.kind_of? Hash
      v+= values(val, key)
    else
      val.each {|i| v+= values(i, key)}
    end
  end
  return v
end

puts values(h, :blending_mode).inspect # h is the Hash from your gist
# => ["normal", "normal", "normal", "normal", "normal", "normal", "normal", "normal", "normal", "normal", "normal", "normal", "normal", "normal", "normal", "normal", "normal", "normal", "normal", "normal", "normal", "normal", "normal", "normal", "normal", "normal", "normal", "normal", "normal", "normal", "normal", "normal", "normal", "normal", "normal", "normal", "normal", "normal", "normal", "normal", "normal", "normal", "normal", "normal", "normal", "normal", "normal", "normal", "normal", "normal", "normal", "normal", "normal", "normal", "normal", "normal", "normal", "normal", "normal", "normal", "normal", "normal", "normal", "normal", "normal", "normal", "normal", "normal", "normal", "normal", "normal", "normal", "normal", "normal", "normal"]

来源：https://stackoverflow.com/questions/17990332/return-single-key-from-nested-hash-in-ruby