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fix: specify dtype for read_csv method #88

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fix: specify dtype for read_csv method #88

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2 changes: 1 addition & 1 deletion filter/filter.py
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Original file line number Diff line number Diff line change
Expand Up @@ -62,7 +62,7 @@ def filter_file(args):
"""
logger.info('Started reading input file')
try:
file = pd.read_csv(args.input_file)
file = pd.read_csv(args.input_file, dtype='unicode')
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I'm not a Python expert so I may be wrong but, since the script is supposed to be run with Python 3, shouldn't it be dtype='str' ?

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@jbelien i just read this stackoverflow post:
https://stackoverflow.com/questions/24251219/pandas-read-csv-low-memory-and-dtype-options
According to this post the proposed code should silence the error, but it does not resolve the main problem.
pandas is trying to guess the datatype for every csv column, but to do this, it has to load in all the data in memory.

If i get it correctly, the proper way to do it is to explicitly state the numpy datatypes for each column in order to make the code more efficient. I am not sure what implications this has on the rest on the code, so for now we can definitely accept this push request, but we should further investigate on this issue in the future.

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I'm not a Python developer either, this code change seemed to fix the issue. It tells panda to treat each column as unicode, which resolves the issue for strings, numbers, ... The fix has been working for several months now on my own fork, but could (temporarily) be applied here too. But I agree this should be further investigated by someone with more knowledge on Python and the panda module.

logger.info('Read input file')
except IOError as io:
logger.fatal(io)
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