scan all elements from a dynamodb table using Python (boto3)

scan.py

from __future__ import print_function # Python 2/3 compatibility
import boto3
import json
import decimal
from boto3.dynamodb.conditions import Key, Attr

# Helper class to convert a DynamoDB item to JSON.
class DecimalEncoder(json.JSONEncoder):
    def default(self, o):
        if isinstance(o, decimal.Decimal):
            if o % 1 > 0:
                return float(o)
            else:
                return int(o)
        return super(DecimalEncoder, self).default(o)

dynamodb = boto3.resource('dynamodb') # may require parameters if not using default AWS environment vars

table = dynamodb.Table('Movies')

fe = Key('year').between(1950, 1959);
pe = "#yr, title, info.rating"
# Expression Attribute Names for Projection Expression only.
ean = { "#yr": "year", } # aliases for reserved keywords
# http://docs.aws.amazon.com/amazondynamodb/latest/developerguide/ReservedWords.html
esk = None

response = table.scan(
    FilterExpression=fe,
    ProjectionExpression=pe,
    ExpressionAttributeNames=ean
    )

for i in response['Items']:
    print(json.dumps(i, cls=DecimalEncoder))
    # or do something else, like items.append(i)

while 'LastEvaluatedKey' in response:
    response = table.scan(
        ProjectionExpression=pe,
        FilterExpression=fe,
        ExpressionAttributeNames= ean,
        ExclusiveStartKey=response['LastEvaluatedKey']
        )

    for i in response['Items']:
        print(json.dumps(i, cls=DecimalEncoder))
        # or do something else, like items.append(i)

Thank you very much! As a newbie at DynamoDB, this saved my life!

Big thank you, this really helps.

Its great. Thanks a lot. Not implementing the while loop after the scan failed my script. Anyways it works now implementing this.

Amazing, thanks! I was about to implement this in a much more verbose way by myself. Very clever to use json library to do the parsing 👌

Thank you!
Why do we need to use while loop?
Answer - https://stackoverflow.com/a/52757046/9783262

Thank you so much. It worked great.