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Move different elements to another array in MongoDB?
Use forEach and check for the different elements and use save() along with some condition. Let us create a collection with documents −
> db.demo646.insertOne(
... {
...
... "Information": [
... { id: 100, Name:"Chris" },
... { id: 100, Name:"Chris" },
... { id: 101, Name:"David" },
... { id: 100, Name:"Chris" }
... ],
... "different": []
... }
... )
{
"acknowledged" : true,
"insertedId" : ObjectId("5e9c82ec6c954c74be91e6ed")
}Display all documents from a collection with the help of find() method −
> db.demo646.find().pretty();
This will produce the following output −
{
"_id" : ObjectId("5e9c82ec6c954c74be91e6ed"),
"Information" : [
{
"id" : 100,
"Name" : "Chris"
},
{
"id" : 100,
"Name" : "Chris"
},
{
"id" : 101,
"Name" : "David"
},
{
"id" : 100,
"Name" : "Chris"
}
],
"different" : [ ]
}Following is the query to move elements to another array −
> db.demo646.find({}).forEach(function(d) {
... d.different = d.Information.filter(function(v) { return v.id == 101 })
... d.Information = d.Information.filter(function(v) { return v.id != 101 })
... db.demo646.save(d)
... }
... )Display all documents from a collection with the help of find() method −
> db.demo646.find().pretty();
This will produce the following output −
{
"_id" : ObjectId("5e9c82ec6c954c74be91e6ed"),
"Information" : [
{
"id" : 100,
"Name" : "Chris"
},
{
"id" : 100,
"Name" : "Chris"
},
{
"id" : 100,
"Name" : "Chris"
}
],
"different" : [
{
"id" : 101,
"Name" : "David"
}
]
}
Updated on: 12-May-2020
236 Views
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