Question 115377 in Mongodb Question posted in
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Update a value for each document inside an array of a collection in MongoDB

I have a MongoDB Collection with objects of type:

{
  id: 1223
  items: [{
    length: 12.233333,
  }, {
    length: 4.2323232323232,
  }]
}

How can I update the length of each item by rounding to 2 decimals.

Tags:

2

Answers


  1. 0

    You can use $round operator like this:

    db.collection.update({},
[
  {
    "$set": {
      "items": {
        $map: {
          input: "$items",
          as: "item",
          in: {
            length: {
              $round: [
                "$$item.length",
                2
              ]
            }
          }
        }
      }
    }
  }
])

    Playground link.

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  2. 0

    Try this one:

    db.collection.aggregate([
   {
      $set: {
         items: {
            $map: {
               input: "$items",
               in: { length: { $round: ["$$this.length", 2] } }
            }
         }
      }
   }
]);

    Mongo Playground

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