What does python with statement do when opening files?

Question

I think that

with open('file.txt','r') as f:
    pass

closes file f, but, how can I prove it? My colleague thinks it will flush the file if it is open for writing.

https://docs.python.org/3.6/tutorial/inputoutput.html#reading-and-writing-files — , Nov 02 '17 at 01:42
actually, https://docs.python.org/3.6/reference/compound_stmts.html#with — cowbert, Nov 02 '17 at 01:44

score 1 · Answer 1 · answered Nov 02 '17 at 01:55

However, if that is not proof enough - here is a way you can check for yourself;

Files have a .closed property that you can check.

with open("file.txt", "r") as f:
    print(f.closed)  # will print False
print(f.closed)  # will print True

The same property can be used when dealing with files the non-with way.

f = open("file.txt", "r")
print(f.closed)  # will print False
f.close()
print(f.closed)  # will print True.

This should service as sufficient proof that the file is indeed being closed.

Yes: close implies flush. See https://stackoverflow.com/questions/2447143/does-close-imply-flush-in-python — Shadow, Nov 02 '17 at 02:06

1 Answers1