df.to_csv function prints out the content instead of writing data to a file

Question

df.to_csv(output_file) is supposed to write the content of a DataFrame to a file. While the function is working for 99.9% of the file in my directory, there is this one file where the function prints out the content of the file instead of writing it to a directory. Then, when I run a pd.read_csv(output_file), the program will get stuck there for a very long time without showing an actual FileNotFound error. Here is the code:

output = is_ldzr('CON_200811010000_200903310000.txt')
print(output)
output.to_csv('CON.csv', index=False, date_format='%Y-%m-%d %H:%M')
print(os.getcwd())
df = pd.read_csv('CON.csv')
print(df)

And the output:

           start_time            end_time  label
0 2008-12-11 12:48:00 2008-12-12 04:23:00      0
1 2008-12-17 16:51:00 2008-12-17 18:51:00      0
2 2008-12-24 13:48:00 2008-12-24 16:51:00      0
3 2009-01-05 07:51:00 2009-01-05 07:51:00      0
4 2009-01-07 14:02:00 2009-01-08 02:26:00      0
5 2009-01-28 23:32:00 2009-01-29 01:09:00      0
start_time,end_time,label
2008-12-11 12:48,2008-12-12 04:23,0
2008-12-17 16:51,2008-12-17 18:51,0
2008-12-24 13:48,2008-12-24 16:51,0
2009-01-05 07:51,2009-01-05 07:51,0
2009-01-07 14:02,2009-01-08 02:26,0
2009-01-28 23:32,2009-01-29 01:09,0
E:\icestorm
... stuck here for a long time. Ctrl + C produces no Traceback. 

As you can see from the output, print(output) prints the DataFrame for the first time, whereas output.to_csv() prints the DataFrame for a second time, now in the format of a string that is supposed to be written into the file CON.csv. pd.read_csv('CON.csv') doesn't read in the data nor produces any error, which is very weird.

In case anyone wants to reproduce the error themselves, I have uploaded the code and the file that is producing the error (there are thousands of other files that worked) to Google drive: https://drive.google.com/drive/folders/1ih_8C3uWsvv9ZsjtZ2VzuzdJ7FG-hUjX?usp=sharing. I am running Python 3.6.5.

Update:

This doesn't produce an error when running on a jupyter notebook on a server, but it is having this weird bug on my laptop. I have tried different Python versions to no avail.

Answer 1

You must be on Windows. This happens because 'CON' is a reserved name (no matter the extension), and Windows will refuse to write a file with such a name to disk.

Answer 2

I now highly doubt that this issue can be reproduced anywhere other than my laptop. Still don't know why it happens, but I will not delete this post in case anyone runs into this mysterious issue later.