List faces in an Amazon Rekognition collection using an AWS SDK

The following code examples show how to list faces in an Amazon Rekognition collection.

For more information, see Listing faces in a collection.

.NET

AWS SDK for .NET

Note

There's more on GitHub. Find the complete example and learn how to set up and run in the AWS Code Examples Repository.

    using System;
    using System.Threading.Tasks;
    using Amazon.Rekognition;
    using Amazon.Rekognition.Model;

    /// <summary>
    /// Uses the Amazon Rekognition Service to retrieve the list of faces
    /// stored in a collection. The example was created using AWS SDK for
    /// .NET version 3.7 and .NET Core 5.0.
    /// </summary>
    public class ListFaces
    {
        public static async Task Main()
        {
            string collectionId = "MyCollection2";

            var rekognitionClient = new AmazonRekognitionClient();

            var listFacesResponse = new ListFacesResponse();
            Console.WriteLine($"Faces in collection {collectionId}");

            var listFacesRequest = new ListFacesRequest
            {
                CollectionId = collectionId,
                MaxResults = 1,
            };

            do
            {
                listFacesResponse = await rekognitionClient.ListFacesAsync(listFacesRequest);
                listFacesResponse.Faces.ForEach(face =>
                {
                    Console.WriteLine(face.FaceId);
                });

                listFacesRequest.NextToken = listFacesResponse.NextToken;
            }
            while (!string.IsNullOrEmpty(listFacesResponse.NextToken));
        }
    }

• For API details, see ListFaces in AWS SDK for .NET API Reference.

Java

SDK for Java 2.x

Note

There's more on GitHub. Find the complete example and learn how to set up and run in the AWS Code Examples Repository.

    public static void listFacesCollection(RekognitionClient rekClient, String collectionId ) {
        try {
            ListFacesRequest facesRequest = ListFacesRequest.builder()
                .collectionId(collectionId)
                .maxResults(10)
                .build();

            ListFacesResponse facesResponse = rekClient.listFaces(facesRequest);
            List<Face> faces = facesResponse.faces();
            for (Face face: faces) {
                System.out.println("Confidence level there is a face: "+face.confidence());
                System.out.println("The face Id value is "+face.faceId());
            }

        } catch (RekognitionException e) {
            System.out.println(e.getMessage());
            System.exit(1);
         }
      }

• For API details, see ListFaces in AWS SDK for Java 2.x API Reference.

Kotlin

SDK for Kotlin

Note

This is prerelease documentation for a feature in preview release. It is subject to change.

Note

There's more on GitHub. Find the complete example and learn how to set up and run in the AWS Code Examples Repository.

suspend fun listFacesCollection(collectionIdVal: String?) {

    val request = ListFacesRequest {
        collectionId = collectionIdVal
        maxResults = 10
    }

    RekognitionClient { region = "us-east-1" }.use { rekClient ->
        val response = rekClient.listFaces(request)
        response.faces?.forEach { face ->
            println("Confidence level there is a face: ${face.confidence}")
            println("The face Id value is ${face.faceId}")
        }
    }
}

• For API details, see ListFaces in AWS SDK for Kotlin API reference.

Python

SDK for Python (Boto3)

Note

There's more on GitHub. Find the complete example and learn how to set up and run in the AWS Code Examples Repository.

class RekognitionCollection:
    """
    Encapsulates an Amazon Rekognition collection. This class is a thin wrapper
    around parts of the Boto3 Amazon Rekognition API.
    """
    def __init__(self, collection, rekognition_client):
        """
        Initializes a collection object.

        :param collection: Collection data in the format returned by a call to
                           create_collection.
        :param rekognition_client: A Boto3 Rekognition client.
        """
        self.collection_id = collection['CollectionId']
        self.collection_arn, self.face_count, self.created = self._unpack_collection(
            collection)
        self.rekognition_client = rekognition_client

    @staticmethod
    def _unpack_collection(collection):
        """
        Unpacks optional parts of a collection that can be returned by
        describe_collection.

        :param collection: The collection data.
        :return: A tuple of the data in the collection.
        """
        return (
            collection.get('CollectionArn'),
            collection.get('FaceCount', 0),
            collection.get('CreationTimestamp'))

    def list_faces(self, max_results):
        """
        Lists the faces currently indexed in the collection.

        :param max_results: The maximum number of faces to return.
        :return: The list of faces in the collection.
        """
        try:
            response = self.rekognition_client.list_faces(
                CollectionId=self.collection_id, MaxResults=max_results)
            faces = [RekognitionFace(face) for face in response['Faces']]
            logger.info(
                "Found %s faces in collection %s.", len(faces), self.collection_id)
        except ClientError:
            logger.exception(
                "Couldn't list faces in collection %s.", self.collection_id)
            raise
        else:
            return faces

• For API details, see ListFaces in AWS SDK for Python (Boto3) API Reference.