python - How to record bad lines skipped by pandas

Question

I'm reading a CSV file with pandas with

error_bad_lines=False

A warning is printed when a bad line is encountered. However, I want to keep a record of all the bad line numbers to feed into another program. Is there an easy way of doing that?

I thought about iterating over the file with a

chunksize=1

and catching the CParserError that ought to be thrown for each bad line encountered. When I do this though no CParserError is thrown for bad lines so I can't catch them.

Answer 1

Warnings are printed in the standard error channel. You can capture them to a file by redirecting the sys.stderr output.

import sys
import pandas as pd

with open('bad_lines.txt', 'w') as fp:
    sys.stderr = fp
    pd.read_csv('my_data.csv', error_bad_lines=False)