$trim

New from version 4.0

The $trim operator in Amazon DocumentDB is used to remove leading and/or trailing whitespace characters from a string.

Parameters

• input: The string expression to trim.

• chars: (optional) Specifies the characters to trim from the beginning and end of the input, the default is whitespace.

Example (MongoDB Shell)

The following example demonstrates how to use the $trim operator to remove leading and trailing whitespace from a string.

Create sample documents

db.people.insertMany([
  { "name": "   John Doe   " },
  { "name": "   Bob Johnson   " }
])

Query example

db.people.aggregate([
  { $project: {
    "name": { $trim: {input: "$name"}}
  }}
])

Output

[
  { "name": "John Doe" },
  { "name": "Bob Johnson" }
]

Code examples

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

Node.js

const { MongoClient } = require('mongodb');

async function example() {
  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('people');

  const result = await collection.aggregate([
    { $project: {
      "name": { $trim: {input: "$name" }}
    }}
  ]).toArray();

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

example();

Python

from pymongo import MongoClient

def example():
    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['people']

    result = list(collection.aggregate([
        {"$project": {
            "name": {"$trim": {"input": "$name"}}
        }}
    ]))

    print(result)
    client.close()

example()