ruby - 散列成分组数组

Question

我对ruby不是很有经验，所以我正在努力格式化一段数据。

我有这个散列，其中包含一些具有相同值的键，例如:

{"key" => "value1", "key2" => "value2", "key3" => "value3", "key4" => "value1", "key5" => "value2" ..}

我想把它变成一个包含按值分组的键的数组

 [["key","key4"],["key2","key5"],["key3"]]

Answer 1

new_hash = {}
hash.each do |key, value|
  new_hash[value] ||= []
  new_hash[value] << key
end
array = new_hash.values # => [["key", "key4"], ["key2", "key5"], ["key3"]]