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"
    }]
}]

我想要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中我只想推进一个新数组......但是在Ruby中可以使用group_by或collect来实现这个目标吗？

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"}]

Answer 2

map和flatten会为您提供所需的输出：

your_array.map {|hash| hash[:entries]}.flatten

#=> [{: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"}]

从key创建新的数组数组

2 个答案: