从 S3 读取 ORC 文件到 Pandas

Question

我正在尝试将 orc 文件从 s3 读取到 Pandas 数据帧中。在我的 pandas 版本中没有 pd.read_orc(...).

我试过这样做：

session = boto3.Session()
s3_client = session.client('s3')

s3_key = "my_object_key"


data = s3_client.get_object(
    Bucket='my_bucket',
    Key=s3_key
)

orc_bytes = data['Body'].read()

以字节形式读取对象。

现在我尝试这样做：

orc_data = pyorc.Reader(orc_bytes)

但它失败了，因为：

---------------------------------------------------------------------------
TypeError                                 Traceback (most recent call last)
<ipython-input-11-deaabe8232ce> in <module>
----> 1 data = pyorc.Reader(orc_data)

/anaconda3/envs/linear_opt_3.7/lib/python3.7/site-packages/pyorc/reader.py in __init__(self, fileo, batch_size, column_indices, column_names, struct_repr, converters)
     65             conv = converters
     66         super().__init__(
---> 67             fileo, batch_size, column_indices, column_names, struct_repr, conv
     68         )
     69 

TypeError: Parameter must be a file-like object, but `<class 'bytes'>` was provided

最终我想将其作为 .csv 格式或我可以读入的内容 pandas。有更好的方法吗？

Answer 1

尝试将 S3 数据包装在 io.BytesIO:

import io

orc_bytes = io.BytesIO(data['Body'].read())
orc_data = pyorc.Reader(orc_bytes)

Answer 2

这是解决问题的函数：

import boto3
import pyorc
import io
import pandas as pd

session = boto3.Session()
s3_client = session.client('s3')

def load_s3_orc_to_local_df(key, bucket):
    data = s3_client.get_object(Bucket=bucket, Key=key)
    orc_bytes = io.BytesIO(data['Body'].read())   
    reader = pyorc.Reader(orc_bytes)
    schema = reader.schema
    columns = [item for item in schema.fields]
    rows = [row for row in reader]   
    df = pd.DataFrame(data=rows, columns=columns)
    return df

从 S3 读取 ORC 文件到 Pandas

Read ORC file from S3 to Pandas

python

amazon-s3

pandas

orc