check if a file is open in Python

I assume that you're writing to the file, then closing it (so the user can open it in Excel), and then, before re-opening it for append/write operations, you want to check that the file isn't still open in Excel?

This is how you could do that:

while True:   # repeat until the try statement succeeds
    try:
        myfile = open("myfile.csv", "r+") # or "a+", whatever you need
        break                             # exit the loop
    except IOError:
        input("Could not open file! Please close Excel. Press Enter to retry.")
        # restart the loop

with myfile:
    do_stuff()

None of the other provided examples would work for me when dealing with this specific issue with excel on windows 10. The only other option I could think of was to try and rename the file or directory containing the file temporarily, then rename it back.

import os

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

If all you care about is the current process, an easy way is to use the file object attribute "closed"

f = open('file.py')
if f.closed:
  print 'file is closed'

This will not detect if the file is open by other processes!

source: http://docs.python.org/2.4/lib/bltin-file-objects.html