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$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
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()