如何使用 boto3 中的 put_item 方法将 dict 列表添加到 DynamoDB

Question

I am having trouble using the client.put_item method to put a list of dicts to my table. The dict is in the form: {"name": "beef", "price":5.23} . An example of a list like this is: [{"name": "chicken", "price":6.23}, {"name": "beef", "price":5.34}, {"name": "pork", "price":8.48}] where the list size could vary . So far I have

def create_order(order_id, cart, total):
    dynamodb = boto3.client('dynamodb')
    table = 'Orders'
    response = dynamodb.put_item(TableName=table,
       Item={
            'order_id': {"S":order_id},
            'order_total': {"N":str(total)},
            'cart':{"L":cart}
            
        }
    )
    return response

It works with order_id and order_total, but I can't figure out how to format the cart.

Answer 1

Couple of things to Note:

• We don't need to specify the type, dynamo client will assume the type based on python variable type
• Floats are not acceptable( open issue ), so, easiest way to covert to json and back to object with parse_float=Decimal .

Here is an example:

import json
import boto3
from decimal import Decimal
dynamodb = boto3.resource('dynamodb',region_name='us-east-1')
table = dynamodb.Table('Orders')
order_id = "1000"
total = 100
cartBefore = [{"name": "chicken", "price":6.23}, {"name": "beef", "price":5.34}, {"name": "pork", "price":8.48}]
cart = json.loads(json.dumps(cartBefore), parse_float=Decimal)
response = table.put_item(
        Item={
                'id': '10',  
                'order_id': order_id,
                'order_total': total,
                'cart': cart

        }
)