ruby - 我有一个 Ruby 对象数组，如何根据这些对象的属性将此数组更改为多个数组？

Question

根据原始数组中对象的属性，将一个大数组更改为多个子数组的最佳方法是什么？例如我有一个对象数组(所有对象都具有相同的属性):

array = [
    {:name => "Jim", :amount => "20"},
    {:name => "Jim", :amount => "40"},
    {:name => "Jim", :amount => "30"},
    {:name => "Eddie", :amount => "7"},
    {:name => "Eddie", :amount => "12"},
    {:name => "Pony", :amount => "330"},
    {:name => "Pony", :amount => "220"},
    {:name => "Pony", :amount => "50"}
]

请注意，具有相同名称 属性的所有对象在数组中都是连续的。现在我想根据名称属性将对象分组到子数组中。我需要的是:

result = [
    [
        {:name => "Jim", :amount => "20"},
        {:name => "Jim", :amount => "40"},
        {:name => "Jim", :amount => "30"}
    ],
    [
        {:name => "Eddie", :amount => "7"},
        {:name => "Eddie", :amount => "12"}
    ],
    [
        {:name => "Pony", :amount => "330"},
        {:name => "Pony", :amount => "220"},
        {:name => "Pony", :amount => "50"}
    ]
]

执行此操作的最佳方法是什么？ 谢谢。

Answer 1

使用group_by繁重的工作然后 map拉出你想要的东西:

result = array.group_by { |h| h[:name] }.map { |k, v| v }

例如:

>> results = array.group_by { |h| h[:name] }.map { |k, v| v }
>> pp results
[[{:name=>"Jim", :amount=>"20"},
  {:name=>"Jim", :amount=>"40"},
  {:name=>"Jim", :amount=>"30"}],
 [{:name=>"Eddie", :amount=>"7"},
  {:name=>"Eddie", :amount=>"12"}],
 [{:name=>"Pony", :amount=>"330"},
  {:name=>"Pony", :amount=>"220"},
  {:name=>"Pony", :amount=>"50"}]]

您也可以跳过 map ，直接前往Hash#values。 :

result = array.group_by { |h| h[:name] }.values

感谢转至 KandadaBoggu感谢您指出这一疏忽。