AWS Documentation » Amazon Rekognition » Developer Guide » Searching Faces in a Collection » Listing Collections

Listing Collections

You can use the ListCollections operation to list the collections in the region that you are using.

For more information, see Managing Collections.

To list collections (SDK)

1. If you haven't already:

   1. Create or update an IAM user with AmazonRekognitionFullAccess permissions. For more information, see Step 1: Set Up an AWS Account and Create an IAM User.

   2. Install and configure the AWS CLI and the AWS SDKs. For more information, see Step 2: Set Up the AWS CLI and AWS SDKs.

2. Use the following examples to call the ListCollections operation.

   JavaAWS CLIPython.NET

   Java

   The following example lists the collections in the current region.

   //Copyright 2018 Amazon.com, Inc. or its affiliates. All Rights Reserved.
   //PDX-License-Identifier: MIT-0 (For details, see https://github.com/awsdocs/amazon-rekognition-developer-guide/blob/master/LICENSE-SAMPLECODE.)
   
   package aws.example.rekognition.image;
   
   import java.util.List;
   import com.amazonaws.services.rekognition.AmazonRekognition;
   import com.amazonaws.services.rekognition.AmazonRekognitionClientBuilder;
   import com.amazonaws.services.rekognition.model.ListCollectionsRequest;
   import com.amazonaws.services.rekognition.model.ListCollectionsResult;
   
   public class ListCollections {
   
      public static void main(String[] args) throws Exception {
   
   
         AmazonRekognition amazonRekognition = AmazonRekognitionClientBuilder.defaultClient();
    
   
         System.out.println("Listing collections");
         int limit = 10;
         ListCollectionsResult listCollectionsResult = null;
         String paginationToken = null;
         do {
            if (listCollectionsResult != null) {
               paginationToken = listCollectionsResult.getNextToken();
            }
            ListCollectionsRequest listCollectionsRequest = new ListCollectionsRequest()
                    .withMaxResults(limit)
                    .withNextToken(paginationToken);
            listCollectionsResult=amazonRekognition.listCollections(listCollectionsRequest);
            
            List < String > collectionIds = listCollectionsResult.getCollectionIds();
            for (String resultId: collectionIds) {
               System.out.println(resultId);
            }
         } while (listCollectionsResult != null && listCollectionsResult.getNextToken() !=
            null);
        
      } 
   }

   AWS CLI

   This AWS CLI command displays the JSON output for the list-collections CLI operation.

   aws rekognition list-collections 

   Python

   The following example lists the collections in the current region.

   #Copyright 2018 Amazon.com, Inc. or its affiliates. All Rights Reserved.
   #PDX-License-Identifier: MIT-0 (For details, see https://github.com/awsdocs/amazon-rekognition-developer-guide/blob/master/LICENSE-SAMPLECODE.)
   
   import boto3
   
   if __name__ == "__main__":
   
       maxResults=2
       
       client=boto3.client('rekognition')
   
       #Display all the collections
       print('Displaying collections...')
       response=client.list_collections(MaxResults=maxResults)
   
       while True:
           collections=response['CollectionIds']
   
           for collection in collections:
               print (collection)
           if 'NextToken' in response:
               nextToken=response['NextToken']
               response=client.list_collections(NextToken=nextToken,MaxResults=maxResults)
               
           else:
               break
   
       print('done...')     
   
   

   .NET

   The following example lists the collections in the current region.

   //Copyright 2018 Amazon.com, Inc. or its affiliates. All Rights Reserved.
   //PDX-License-Identifier: MIT-0 (For details, see https://github.com/awsdocs/amazon-rekognition-developer-guide/blob/master/LICENSE-SAMPLECODE.)
   
   using System;
   using Amazon.Rekognition;
   using Amazon.Rekognition.Model;
   
   public class ListCollections
   {
       public static void Example()
       {
           AmazonRekognitionClient rekognitionClient = new AmazonRekognitionClient();
   
           Console.WriteLine("Listing collections");
           int limit = 10;
   
           ListCollectionsResponse listCollectionsResponse = null;
           String paginationToken = null;
           do
           {
               if (listCollectionsResponse != null)
                   paginationToken = listCollectionsResponse.NextToken;
   
               ListCollectionsRequest listCollectionsRequest = new ListCollectionsRequest()
               {
                   MaxResults = limit,
                   NextToken = paginationToken
               };
   
               listCollectionsResponse = rekognitionClient.ListCollections(listCollectionsRequest);
   
               foreach (String resultId in listCollectionsResponse.CollectionIds)
                   Console.WriteLine(resultId);
           } while (listCollectionsResponse != null && listCollectionsResponse.NextToken != null);
       }
   }
   

ListCollections Operation Request

The input to ListCollections is the maximum number of collections to be returned.

{
    "MaxResults": 2
}

If the response has more faces than requested by MaxResults, a token is returned that you can use to get the next set of results, in a subsequent call to ListCollections. For example:

{
    "NextToken": "MGYZLAHX1T5a....",
    "MaxResults": 2
}

ListCollections Operation Response

Amazon Rekognition returns an array of collections (CollectionIds). A separate array (FaceModelversions) provides the version of the face model used to analyze faces in each collection. For example, in the following JSON response, the collection MyCollection analyzes faces by using version 2.0 of the face model. The collection AnotherCollection uses version 3.0 of the face model. For more information, see Model Versioning.

NextToken is the token that's used to get the next set of results, in a subsequent call to ListCollections.

{
    "CollectionIds": [
        "MyCollection",
        "AnotherCollection"
    ],
    "FaceModelVersions": [
        "2.0",
        "3.0"
    ],
    "NextToken": "MGYZLAHX1T5a...."
}