Ruby – 从散列数组中提取每个键的唯一值

从下面的哈希值中，需要提取每个键的唯一值

array_of_hashes = [ {'a' => 1, 'b' => 2 , 'c' => 3} , {'a' => 4, 'b' => 5 , 'c' => 3}, {'a' => 6, 'b' => 5 , 'c' => 3} ] 

需要提取数组中每个键的唯一值

‘a’的唯一值应该给出

 [1,4,6] 

‘b’的唯一值应该给出

 [2,5] 

‘c’的唯一值应该给出

 [3] 

想法？

Answer 1

使用Array#uniq ：

 array_of_hashes = [ {'a' => 1, 'b' => 2 , 'c' => 3} , {'a' => 4, 'b' => 5 , 'c' => 3}, {'a' => 6, 'b' => 5 , 'c' => 3} ] array_of_hashes.map { |h| h['a'] }.uniq # => [1, 4, 6] array_of_hashes.map { |h| h['b'] }.uniq # => [2, 5] array_of_hashes.map { |h| h['c'] }.uniq # => [3] 

Answer 2

这更通用：

 options = {} distinct_keys = array_of_hashes.map(&:keys).flatten.uniq distinct_keys.each do |k| options[k] = array_of_hashes.map {|o| o[k]}.uniq end