From array of objects to just array

Question

I have a query db.collection('image').find({ category: "concept art"}, { projection: _id: 0, imgUrl:1 }).toArray() and have an output:

[
    {
        "imgUrl": "images\\2020-01-23T14-41-48.158Z-abandoned.jpg"
    },
    {
        "imgUrl": "images\\2020-01-25T01-45-14.880Z-pIMG_6443.jpg"
    }
]

I want an output like this:

[
"images\\2020-01-23T14-41-48.158Z-abandoned.jpg",
  "images\\2020-01-25T01-45-14.880Z-pIMG_6443.jpg"
]

Where can I find some information about this or how to achieve this?

whoami - fakeFaceTrueSoul · Accepted Answer · 2020-01-25 04:24:50Z

2

You need to try aggregation for that :

db.collection.aggregate([
    /** match docs based on criteria same as find */
    { $match: { "category": "concept art" } },
    /** group all docs and push imageUrls to an array */
    { $group: { _id: '', imgUrl: { $push: '$imgUrl' } } },
    /** remove _id from final doc */
    { $project: { _id: 0 } }])

Collection Data :

/* 1 */
{
    "_id" : ObjectId("5e2bc27cdc95d08ab83819e8"),
    "category" : "concept art",
    "isImage" : true,
    "imgUrl" : "images\\2020-01-23T14-41-48.158Z-abandoned.jpg"
}

/* 2 */
{
    "_id" : ObjectId("5e2bc27cdc95d08ab83819e9"),
    "category" : "concept art",
    "isImage" : true,
    "imgUrl" : "images\\2020-01-25T01-45-14.880Z-pIMG_6443.jpg"
}

Output :

/* 1 */
{
    "imgUrl" : [ 
        "images\\2020-01-23T14-41-48.158Z-abandoned.jpg", 
        "images\\2020-01-25T01-45-14.880Z-pIMG_6443.jpg"
    ]
}

answered Jan 25, 2020 at 4:24

whoami - fakeFaceTrueSoul

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2 Comments

nukuutos Over a year ago

I got [ { imgUrl: [ data ] } ]. Can I get just [ data ]?

whoami - fakeFaceTrueSoul Over a year ago

@nukuutos : It will return an array of objects or an object, So in your code you can do dbResult.imgUrl

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