Python - test if a file has already been open

Question

I would testing if a file has already been open before writing.

Here my code :

with open(file_five, 'w') as f:
    f.write(xml)

I would something as this code example :

if "file_five has already been open"
        with open(file_five, 'w') as f:
           f.write(xml)
else:
...

What do you mean with 'has been open' earlier opened by your script or ever before? — Dylan_w, May 10 '19 at 10:12
In that case, possible duplicate of [How to check if a file is already opened (in the same process)](https://stackoverflow.com/questions/37515574/how-to-check-if-a-file-is-already-opened-in-the-same-process) — Federico klez Culloca, May 10 '19 at 10:14
@FedericoklezCulloca am not sure it's exactly the same problem. I think OP wants to know if the file has already been opened in the past, not if the file is opened right now.... or i totally misunderstood :D — Flo, May 10 '19 at 10:15
Does it make a difference? You overwrite the file anyhow ... truncating it in the process. — Patrick Artner, May 10 '19 at 10:16
@flo I'd say the question is not clear, if that's the case. OP may want to clarify. — Federico klez Culloca, May 10 '19 at 10:17
Using the `with open(..) as f: ... ` aproach it is quite easy to se if it is open (in your program) - it closes when you leave the scope of the `with ....:` context manager. — Patrick Artner, May 10 '19 at 10:18
My question is testing if the file already been opened in the past — PseudoWithK, May 10 '19 at 10:27
@PseudoWithK and is now closed? Just add a boolean and set it to `True` whenever you open the file, then check if it's `True` before opening again. — Federico klez Culloca, May 10 '19 at 10:30

score -2 · Answer 1 · edited May 10 '19 at 10:18

-2

There are two ways: 1-> For Excel specific

try:
    myfile = open("file_five.csv", "r+") # or "a+", whatever you need
except IOError:
    print "Could not open file! !"

with myfile:
    do_stuff()

2 -> For any file (Rename approach)

import os

try: 
    os.rename('file.xls', 'tempfile.xls')
    os.rename('tempfile.xls', 'file.xls')
except OSError:
    print('File is still open.')

edited May 10 '19 at 10:18

Federico klez Culloca

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answered May 10 '19 at 10:16

ashishmishra

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Python - test if a file has already been open

1 Answers1