check if a file is open in Python

Question

In my app, I write to an excel file. After writing, the user is able to view the file by opening it. But if the user forgets to close the file before any further writing, a warning message should appear. So I need a way to check this file is open before the writing process. Could you supply me with some python code to do this task?

Answer 1

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

Answer 2

I assume that you're writing to the file, then close 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()