# $toUUID
<a name="toUUID"></a>

New from version 8.0.1.

The `$toUUID` operator in Amazon DocumentDB converts a string value to a UUID (Binary subtype 4).

**Parameters**
+ `expression`: An expression that resolves to a string in UUID format (for example, "12345678-1234-1234-1234-123456789abc").

## Example (MongoDB Shell)
<a name="toUUID-examples"></a>

The following example shows how to use the `$toUUID` operator to convert string values to UUID format.

**Create sample documents**

```
db.records.insertMany([
  {_id: 1, uuidStr: "550e8400-e29b-41d4-a716-446655440000"},
  {_id: 2, uuidStr: "6ba7b810-9dad-11d1-80b4-00c04fd430c8"}
]);
```

**Query example**

```
db.records.aggregate([
  { $project: { uuid: { $toUUID: "$uuidStr" } } }
]);
```

**Output**

```
[
  {_id: 1, uuid: UUID("550e8400-e29b-41d4-a716-446655440000")},
  {_id: 2, uuid: UUID("6ba7b810-9dad-11d1-80b4-00c04fd430c8")}
]
```

## Code examples
<a name="toUUID-code"></a>

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

------
#### [ Node.js ]

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

async function example() {
  const client = new MongoClient('mongodb://<username>:<password>@<cluster-endpoint>:27017/?tls=true&tlsCAFile=global-bundle.pem&replicaSet=rs0&readPreference=secondaryPreferred&retryWrites=false');
  try {
    await client.connect();
    const db = client.db('test');
    const collection = db.collection('records');
    const result = await collection.aggregate([
      { $project: { uuid: { $toUUID: "$uuidStr" } } }
    ]).toArray();
    console.log(result);
  } finally {
    await 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')
    try:
        db = client['test']
        collection = db['records']
        result = list(collection.aggregate([
            {'$project': {'uuid': {'$toUUID': '$uuidStr'}}}
        ]))
        print(result)
    finally:
        client.close()

example()
```

------