问题
This is a follow up / updated question to this:
AWS dynamodb support for "R" programming language
I am looking for examples or documentation on how to read in a table from DynamoDB into R.
This question pointed me in the right direction:
R + httr and EC2 api authentication issues
(answered by the great @hadley himself!).
It's ok if I have to use httr and then parse a json response, but I can't even figure out how to format the POST request.
Thanks!
回答1:
Repeating my answer from here since someone sent me this page asking a similar question.
Here's a simplified version of what I'm using for reading data from DynamoDB into R. It relies on the fact that R and Python can exchange data, and a library called boto in Python makes it really easy to get data from DynamoDB. It would be neat if this was all an R package, but I won't complain given the 25GB of free storage you can get from Amazon.
First, you need a Python script like so named query_dynamo.py:
import boto3
import time
dynamodb = boto3.resource('dynamodb',
aws_access_key_id='<GET ME FROM AWS>',
aws_secret_access_key='<ALSO GET ME FROM AWS CONSOLE>',
region_name='us-east-1')
table = dynamodb.Table('comment') ###Your table name in DynamoDB here
response = table.scan()
data = response['Items']
while 'LastEvaluatedKey' in response:
response = table.scan(ExclusiveStartKey=response['LastEvaluatedKey'])
data.extend(response['Items'])
Then in R you do this. If you're trying this on Windows, you may want to try rPython-win instead. I did all this on Ubuntu Linux 16.04 LTS.
library(rPython)
python.load("query_dynamo.py")
temp = as.data.frame(python.get('data'))
df = as.data.frame(t(temp))
rm(temp)
Now you'll have a dataframe called "df" with the contents of whatever you put in DynamoDB.
回答2:
You could stream updates to your DynamoDB table with a Lambda function to Connect to Redshift as you would connect to a SQL database, and then perform the big data analytics you need against Redshift.
来源：https://stackoverflow.com/questions/18936162/r-language-support-for-aws-dynamodb