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$cos - Amazon DocumentDB
Example (MongoDB Shell)Code examples

$cos

New from version 8.0.1.

The $cos operator in Amazon DocumentDB returns the cosine of a value that is measured in radians. Use it in the aggregation pipeline to perform trigonometric calculations on numeric fields.

Parameters

  • expression: An expression that resolves to a number in radians.

Example (MongoDB Shell)

The following example shows how to use the $cos operator to calculate the cosine of angle values in radians.

Create sample documents

db.angles.insertMany([
  { "_id": 1, "angle": 0 },
  { "_id": 2, "angle": 1.0471975511965976 },
  { "_id": 3, "angle": 3.141592653589793 }
]);

Query example

db.angles.aggregate([
  { $project: {
    "cosine": { $cos: "$angle" }
  }}
]);

Output

[
  { "_id": 1, "cosine": 1 },
  { "_id": 2, "cosine": 0.5000000000000001 },
  { "_id": 3, "cosine": -1 }
]

Code examples

To view a code example for using the $cos operator, choose the tab for the language that you want to use:

Node.js
const { MongoClient } = require('mongodb');

async function main() {
  const client = await MongoClient.connect('mongodb://<username>:<password>@<cluster-endpoint>:27017/?tls=true&tlsCAFile=global-bundle.pem&replicaSet=rs0&readPreference=secondaryPreferred&retryWrites=false');
  const db = client.db('test');
  const collection = db.collection('angles');

  const result = await collection.aggregate([
    { $project: {
      "cosine": { $cos: "$angle" }
    }}
  ]).toArray();

  console.log(result);
  await client.close();
}

main();
Python
from pymongo import MongoClient

def main():
    client = MongoClient('mongodb://<username>:<password>@<cluster-endpoint>:27017/?tls=true&tlsCAFile=global-bundle.pem&replicaSet=rs0&readPreference=secondaryPreferred&retryWrites=false')
    db = client['test']
    collection = db['angles']

    result = list(collection.aggregate([
        { '$project': {
            'cosine': { '$cos': '$angle' }
        }}
    ]))

    print(result)
    client.close()

if __name__ == "__main__":
    main()