ruby-on-rails - 从键创建新的数组数组

Question

我有一个数组:

[{
    "name": "Category 1",
    "entries": [{
        "question": "Question 1",
        "answer": "Answer 1"
    }, {
        "question": "Question 2",
        "answer": "Answer 2"
    }, {
        "question": "Question 3",
        "answer": "Answer 3"
    }]
}, {
    "name": "Category 2",
    "entries": [{
        "question": "Question 1",
        "answer": "Answer 1"
    }, {
        "question": "Question 2",
        "answer": "Answer 2"
    }, {
        "question": "Question 3",
        "answer": "Answer 3"
    }]
}]

我想做的是创建一个仅包含条目的新数组。

所以我最终得到了这个:

[{
    "question": "Question 1",
    "answer": "Answer 1"
}, {
    "question": "Question 2",
    "answer": "Answer 2"
}, {
    "question": "Question 3",
    "answer": "Answer 3"
}, {
    "question": "Question 1",
    "answer": "Answer 1"
}, {
    "question": "Question 2",
    "answer": "Answer 2"
}, {
    "question": "Question 3",
    "answer": "Answer 3"
}]

在 PHP 中，我只想将一个新数组插入...但在 Ruby 中，是否可以使用 group_by 或 collect 来实现这一点？

Answer 1

使用Enumerable#flat_map :

array = [{
    "name": "Category 1",
    "entries": [{
        "question": "Question 1",
        "answer": "Answer 1"
    }, {
        "question": "Question 2",
        "answer": "Answer 2"
    }, {
        "question": "Question 3",
        "answer": "Answer 3"
    }]
}, {
    "name": "Category 2",
    "entries": [{
        "question": "Question 1",
        "answer": "Answer 1"
    }, {
        "question": "Question 2",
        "answer": "Answer 2"
    }, {
        "question": "Question 3",
        "answer": "Answer 3"
    }]
}]
array.flat_map { |hash| hash[:entries] }
   #=> [{:question=>"Question 1", :answer=>"Answer 1"},
   #  {:question=>"Question 2", :answer=>"Answer 2"},
   #  {:question=>"Question 3", :answer=>"Answer 3"},
   #  {:question=>"Question 1", :answer=>"Answer 1"},
   #  {:question=>"Question 2", :answer=>"Answer 2"},
   #  {:question=>"Question 3", :answer=>"Answer 3"}]