Delete a file if it exists. If it doesn't, create it

Question

Title says all.

My code:

 try:
        os.remove("NumPyResults.txt")

 except IOError:

        with open("NumPyResults.txt", 'a') as results_file:
            outfile = csv.writer(results_file)
            outfile.writerow(.......)

The reason it is in append is because it is in a function and called numerous times. So I want a new file every time I run the program, by deleting the old one and writing the new one.

However this does not create a new file. I also created the file in the directory I am running from and it doesn't delete it either.

I get

WindowsError: [Error 2] The system cannot find the file specified: 'NumPyResults.txt'

http://stackoverflow.com/questions/2967194/open-in-python-does-not-create-a-file-if-it-doesnt-exist — jarmod, Aug 07 '15 at 15:40
Why not just use `open(path, 'w')`? It deletes the old file and rewrites over it. — Markus Meskanen, Aug 07 '15 at 15:46
All this is inside a function? Won't the file get deleted each time you make a call? — Renae Lider, Aug 07 '15 at 15:48

score 12 · Accepted Answer · edited Aug 07 '15 at 17:32

12

The exception I get for a missing filename is 'OSError', not 'IOError'. And if you get the exception, you just want to pass, and the file writing should be outside the try block.

try:
    os.remove("NumPyResults.txt")
except OSError:
    pass

with open("NumPyResults.txt", 'a') as results_file:
    results_file.write('hi\n')

edited Aug 07 '15 at 17:32

dethtron5000

10,363
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answered Aug 07 '15 at 15:55

Robert E

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For what it's worth, I get `FileNotFoundError` on python3.4 and `OSError` on python2.7 – NightShadeQueen Aug 07 '15 at 16:01

Delete a file if it exists. If it doesn't, create it

1 Answers1