計算數組中的出現次數並在Ruby on Rails中排序

Question

我有一個由Search.all函數返回的數組：

=> [#<Search id: 7, name: "ap", presence: true, created_at: "2012-03-16 00:58:42", updated_at: "2012-03-16 00:58:42">, #<Search id: 8, name: "papier", presence: true, created_at: "2012-03-16 01:14:32", updated_at: "2012-03-16 01:14:32">, #<Search id: 9, name: "carton de jus", presence: true, created_at: "2012-03-20 22:28:53", updated_at: "2012-03-20 22:28:53">, #<Search id: 10, name: "carton de jus", presence: true, created_at: "2012-03-20 22:29:01", updated_at: "2012-03-20 22:29:01">, #<Search id: 11, name: "Papier", presence: true, created_at: "2012-03-22 20:43:36", updated_at: "2012-03-22 20:43:36">, #<Search id: 12, name: "Papier", presence: true, created_at: "2012-03-22 20:43:47", updated_at: "2012-03-22 20:43:47">, #<Search id: 13, name: "Salut", presence: false, created_at: "2012-03-24 20:34:49", updated_at: "2012-03-24 20:34:49">, #<Search id: 14, name: "carton", presence: true, created_at: "2012-03-26 19:32:03", updated_at: "2012-03-26 19:32:03">, #<Search id: 15, name: "carton", presence: true, created_at: "2012-03-26 19:32:11", updated_at: "2012-03-26 19:32:11">, #<Search id: 16, name: "carton", presence: true, created_at: "2012-03-26 19:32:15", updated_at: "2012-03-26 19:32:15">, #<Search id: 17, name: "cellulaire", presence: true, created_at: "2012-03-26 19:32:28", updated_at: "2012-03-26 19:32:28">, #<Search id: 18, name: "cellulaire", presence: true, created_at: "2012-03-26 19:32:36", updated_at: "2012-03-26 19:32:36">, #<Search id: 19, name: "montre", presence: false, created_at: "2012-03-29 00:45:26", updated_at: "2012-03-29 00:45:26">, #<Search id: 20, name: "montre", presence: false, created_at: "2012-03-29 00:45:29", updated_at: "2012-03-29 00:45:29">, #<Search id: 21, name: "montres", presence: false, created_at: "2012-03-29 00:45:32", updated_at: "2012-03-29 00:45:32">, #<Search id: 22, name: "montre", presence: false, created_at: "2012-03-29 00:45:35", updated_at: "2012-03-29 00:45:35">]

我想基於“ name”計算相同元素的出現次數 。 我知道如何找到像這樣的數組中的出現： ['a', 'b', 'a']與

favoris.inject(Hash.new(0)) { |h,v| h[v] += 1; h }

但是如何在以前的數組中使用它呢？

Answer 1

favoris.inject(Hash.new(0)) { |h,v| h[v.name] += 1; h }

:)

Answer 2

我更喜歡基於each的解決方案，因為您實際上是在迭代數組的每個元素時產生副作用。 以我的理解，這不是inject創建的原因。

h = Hash.new(0)
favoris.each { |el| h[el] += 1 }