I'm reading in data from a number of S3 files in PySpark. The S3 keys contain the calendar date that the file was created and I'd like to do a join between the data and that date. Is there any way to do a join between the lines of data in files and filenames?
You can add a column to the dataframe that contains the file name, I use this to identify the source of each row after merging them later:
from pyspark.sql.functions import lit
filename = 'myawesomefile.csv'
df_new = df.withColumn('file_name', lit(filename))
Here's what I ended up doing:
I overwrote the LineRecordReader Hadoop class so that it included the filename in each line, then overwrote TextInputFormat to use my new LineRecordReader.
Then I loaded the file using the newAPIHadoopFile function.
Links:
LineRecordReader: http://tinyurl.com/linerecordreader
TextInputFormat: http://tinyurl.com/textinputformat
newAPIHadoopFile: http://tinyurl.com/newapihadoopfile
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