CODEWITHSUNDEEP
pythonpython-3.xdataframepysparkapache-spark-sql
kev
kev

Reputation: 2881

How to read multiple partitioned .gzip files into a Spark Dataframe?

I have the following folder of partitioned data-

my_folder
 |--part-0000.gzip
 |--part-0001.gzip
 |--part-0002.gzip
 |--part-0003.gzip

I try to read this data into a dataframe using-

>>> my_df = spark.read.csv("/path/to/my_folder/*")
>>> my_df.show(5)
+--------------------+
|                 _c0|
+--------------------+
|��[I���...|
|��RUu�[*Ք��g��T...|
|�t���  �qd��8~��...|
|�(���b4�:������I�...|
|���!y�)�PC��ќ\�...|
+--------------------+
only showing top 5 rows

Also tried using this to check the data-

>>> rdd = sc.textFile("/path/to/my_folder/*")
>>> rdd.take(4)
['\x1f�\x08\x00\x00\x00\x00\x00\x00\x00�͎\\ǖ�7�~�\x04�\x16��\'��"b�\x04�AR_<G��"u��\x06��L�*�7�J�N�\'�qa��\x07\x1ey��\x0b\\�\x13\x0f\x0c\x03\x1e�Q��ڏ�\x15Y_Yde��Y$��Q�JY;s�\x1d����[��\x15k}[B\x01��ˀ�PT��\x12\x07-�\x17\x12�\x0c#\t���T۱\x01yf��\x14�S\x0bc)��\x1ex���axAO˓_\'��`+HM҈�\x12�\x17�@']

NOTE: When I do a zcat part-0000.gzip | head -1 to read the file content, it shows the data is tab separated and in plain readable English.

How do I read these files properly into a dataframe?

Upvotes: 3

Views: 2449

Answers (1)

kev
kev

Reputation: 2881

For some reason, Spark does not recognize the .gzip file extension. So I had to change the file extensions before reading the partitioned data-

import os

# go to my_folder
os.chdir("/path/to/my_folder")

# renaming all `.gzip` extensions to `.gz` within my_folder
cmd = 'rename "s/gzip/gz/" *.gzip'
result_code = os.system(cmd)

if result_code == 0:
    print("Successfully renamed the file extensions!")

    # finally reading the data into a dataframe
    my_df = spark.read.csv("/path/to/my_folder/*", sep="\t")
else:
    print("Could not rename the file extensions!")

Upvotes: 2

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