Question

我有诗集。集合中的文档具有以下结构：

{
"_id" : "Romeo and Juliet",
"acts" : [ 
    {
        "title" : "ACT I",
        "scenes" : [ 
            {
                "title" : "SCENE I. Verona. A public place.",
                "action" : [ 
                    {
                        "character" : "SAMPSON",
                        "says" : [ 
                            "Gregory, o' my word, we'll not carry coals."
                        ]
                    }, 
                    {
                        "character" : "GREGORY",
                        "says" : [ 
                            "No, for then we should be colliers."
                        ]
                    }, 
                    // ...
                    {
                        "character" : "GREGORY",
                        "says" : [ 
                            "To move is to stir; and to be valiant is to stand:", 
                            "therefore, if thou art moved, thou runn'st away."
                        ]
                    }, 
                    {
                        "character" : "SAMPSON",
                        "says" : [ 
                            "A dog of that house shall move me to stand: I will", 
                            "take the wall of any man or maid of Montague's."
                        ]
                    }, 
                    {
                        "character" : "GREGORY",
                        "says" : [ 
                            "That shows thee a weak slave; for the weakest goes", 
                            "to the wall."
                        ]
                    }
                    // ...
                ]
            }
            // ...
        ]
    }
    // ...
]}

我想计算每首诗的行为和场景数量。我试图做这样的事情，但结果是不正确的。

db.poems.aggregate([{$unwind:"$acts"}, {$unwind:"$acts.scenes"}, {$group: {_id: "$_id", pa: {$push: {poemAct:"$acts"}}, ps: {$push: {poemScenes:"$acts.scenes"}}}}, {$project: {numberOfActs: {$size: "$pa"}, numberOfScenes: {$size: "$ps"}}}]).pretty()

请帮助某人：D

Answer 1

您可以尝试以下聚合。此处不需要.parent{ width:250px; height:250px; background-color:green; position:relative; } .child{ display:flex; flex-direction:column; background-color:red; position:absolute; } .box_container{ display:flex; flex-direction:row; align-items:center; } .intro{ position:relative; top:10px } .box{ width:15px; height:15px; background-color:yellow; }。

$map和$size输出具有场景大小和$sum的数组以计算数组值。

$unwind

Answer 2

db.poems.find().forEach(function(poem) {
    var res = {};
    res._id = poem._id, 
    res.acts = poem.acts.length;
    res.scenes = poem.acts.scenes.length;
    printjson(res)
})

MongoD大小的多个嵌套数组

2 个答案: