How to extract elements from a JSON object

Question

I am trying to get the DBInstanceIdentifier value from the below json object (response)

{
    'Marker': 'string',
    'DBInstances': [
        {
            'DBInstanceIdentifier': 'string',
            'DBInstanceClass': 'string',
            'Engine': 'string',
            'DBInstanceStatus': 'string',
            'MasterUsername': 'string',
            'DBName': 'string',
            'Endpoint': {
                'Address': 'string',
                'Port': 123,
                'HostedZoneId': 'string'
            },
            'AllocatedStorage': 123,
            'InstanceCreateTime': datetime(2015, 1, 1),
            'PreferredBackupWindow': 'string',
            'BackupRetentionPeriod': 123,
            'DBSecurityGroups': [
                {
                    'DBSecurityGroupName': 'string',
                    'Status': 'string'
                },
            ],
            'VpcSecurityGroups': [
                {
                    'VpcSecurityGroupId': 'string',
                    'Status': 'string'
                },
            ],
            'DBParameterGroups': [
                {
                    'DBParameterGroupName': 'string',
                    'ParameterApplyStatus': 'string'
                },
            ],
            'AvailabilityZone': 'string',
            'DBSubnetGroup': {
                'DBSubnetGroupName': 'string',
                'DBSubnetGroupDescription': 'string',
                'VpcId': 'string',
                'SubnetGroupStatus': 'string',
                'Subnets': [
                    {
                        'SubnetIdentifier': 'string',
                        'SubnetAvailabilityZone': {
                            'Name': 'string'
                        },
                        'SubnetStatus': 'string'
                    },
                ],
                'DBSubnetGroupArn': 'string'
            },
            'PreferredMaintenanceWindow': 'string',
            'PendingModifiedValues': {
                'DBInstanceClass': 'string',
                'AllocatedStorage': 123,
                'MasterUserPassword': 'string',
                'Port': 123,
                'BackupRetentionPeriod': 123,
                'MultiAZ': True|False,
                'EngineVersion': 'string',
                'LicenseModel': 'string',
                'Iops': 123,
                'DBInstanceIdentifier': 'string',
                'StorageType': 'string',
                'CACertificateIdentifier': 'string',
                'DBSubnetGroupName': 'string',
                'PendingCloudwatchLogsExports': {
                    'LogTypesToEnable': [
                        'string',
                    ],
                    'LogTypesToDisable': [
                        'string',
                    ]
                },
                'ProcessorFeatures': [
                    {
                        'Name': 'string',
                        'Value': 'string'
                    },
                ]
            },
            'LatestRestorableTime': datetime(2015, 1, 1),
            'MultiAZ': True|False,
            'EngineVersion': 'string',
            'AutoMinorVersionUpgrade': True|False,
            'ReadReplicaSourceDBInstanceIdentifier': 'string',
            'ReadReplicaDBInstanceIdentifiers': [
                'string',
            ],
            'ReadReplicaDBClusterIdentifiers': [
                'string',
            ],
            'LicenseModel': 'string',
            'Iops': 123,
            'OptionGroupMemberships': [
                {
                    'OptionGroupName': 'string',
                    'Status': 'string'
                },
            ],
            'CharacterSetName': 'string',
            'SecondaryAvailabilityZone': 'string',
            'PubliclyAccessible': True|False,
            'StatusInfos': [
                {
                    'StatusType': 'string',
                    'Normal': True|False,
                    'Status': 'string',
                    'Message': 'string'
                },
            ],
            'StorageType': 'string',
            'TdeCredentialArn': 'string',
            'DbInstancePort': 123,
            'DBClusterIdentifier': 'string',
            'StorageEncrypted': True|False,
            'KmsKeyId': 'string',
            'DbiResourceId': 'string',
            'CACertificateIdentifier': 'string',
            'DomainMemberships': [
                {
                    'Domain': 'string',
                    'Status': 'string',
                    'FQDN': 'string',
                    'IAMRoleName': 'string'
                },
            ],
            'CopyTagsToSnapshot': True|False,
            'MonitoringInterval': 123,
            'EnhancedMonitoringResourceArn': 'string',
            'MonitoringRoleArn': 'string',
            'PromotionTier': 123,
            'DBInstanceArn': 'string',
            'Timezone': 'string',
            'IAMDatabaseAuthenticationEnabled': True|False,
            'PerformanceInsightsEnabled': True|False,
            'PerformanceInsightsKMSKeyId': 'string',
            'PerformanceInsightsRetentionPeriod': 123,
            'EnabledCloudwatchLogsExports': [
                'string',
            ],
            'ProcessorFeatures': [
                {
                    'Name': 'string',
                    'Value': 'string'
                },
            ],
            'DeletionProtection': True|False,
            'AssociatedRoles': [
                {
                    'RoleArn': 'string',
                    'FeatureName': 'string',
                    'Status': 'string'
                },
            ],
            'ListenerEndpoint': {
                'Address': 'string',
                'Port': 123,
                'HostedZoneId': 'string'
            },
            'MaxAllocatedStorage': 123
        },
    ]
}

Here is what I tried:

response = rds_client.describe_db_instances()
InstanceIdentifierNames = response['DBInstances']['DBInstanceIdentifier']
print(InstanceIdentifierNames)

But I get this error:

TypeError: list indices must be integers or slices, not st

Answer 1

DBInstances is a list of instances, hence you will need to get a given DBInstance before you can get its identifier.

I suspect you want something like the following:

response = rds_client.describe_db_instances()
InstanceIdentifierNames = []
for DBInstance in response['DBInstances']:
  InstanceIdentifierNames.append(DBInstance['DBInstanceIdentifier'])
print(InstanceIdentifierNames)

Answer 2

As DBInstances is list. So try:

 response['DBInstances'][0]['DBInstanceIdentifier']