Write Python DataFrame as CSV into Azure Blob

问题

I got two questions on reading and writing Python objects from/to Azure blob.

1) Can someone tell me how to write Python dataframe as csv file directly into Azure Blob without storing it locally?

I tried using the functions create_blob_from_text & create_blob_from_stream but none of them works.

Converting dataframe to string and using create_blob_from_text function writes the file into the blob but as a plain string but not as csv.

    df_b = df.to_string()
    block_blob_service.create_blob_from_text('test', 'OutFilePy.csv', df_b)  

2) How to directly read a json file in Azure blob storage directly into Python?

回答1:

1) Can someone tell me how to write Python dataframe as csv file directly into Azure Blob without storing it locally?

You could use pandas.DataFrame.to_csv method.

Sample code:

from azure.storage.blob import (
    BlockBlobService
)
import pandas as pd
import io

output = io.StringIO()
head = ["col1" , "col2" , "col3"]
l = [[1 , 2 , 3],[4,5,6] , [8 , 7 , 9]]
df = pd.DataFrame (l , columns = head)
print df
output = df.to_csv (index_label="idx", encoding = "utf-8")
print(output)

accountName = "***"
accountKey = "***"
containerName = "test1"
blobName = "test3.json"

blobService = BlockBlobService(account_name=accountName, account_key=accountKey)

blobService.create_blob_from_text('test1', 'OutFilePy.csv', output)

Output result:

2.How to directly read a json file in Azure blob storage directly into Python?

Sample code:

from azure.storage.blob import (
    BlockBlobService
)

accountName = "***"
accountKey = "***"
containerName = "test1"
blobName = "test3.json"

blobService = BlockBlobService(account_name=accountName, account_key=accountKey)

result = blobService.get_blob_to_text(containerName,blobName)

print(result.content)

Output result:

Hope it helps you.

来源：https://stackoverflow.com/questions/50014827/write-python-dataframe-as-csv-into-azure-blob