Ruby - 从哈希数组中提取每个键的唯一值

Question

从像下面这样的散列中，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

[1,4,6]

'b' 的唯一值应该给

[2,5]

“c”的唯一值应该给

[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]