Instead of this:
FILE = open(f)
do_something(FILE)
FILE.close()
it\'s better to use this:
with open(f) as FILE:
do_some
If you were to just write it like this:
if f is not None:
with open(f) as FILE:
do_something(FILE)
else:
do_something(f)
(file
is a builtin btw )
Update
Here is a funky way to do an on-the-fly context with an optional None that won't crash:
from contextlib import contextmanager
none_context = contextmanager(lambda: iter([None]))()
#
with (open(f) if f is not None else none_context) as FILE:
do_something(FILE)
It creates a context that returns a None value. The with
will either produce FILE as a file object, or a None type. But the None type will have a proper __exit__
Update
If you are using Python 3.7 or higher, then you can declare the null context manager for stand-in purposes in a much simpler way:
import contextlib
none_context = contextlib.nullcontext()
You can read more about these here:
https://docs.python.org/3.7/library/contextlib.html#contextlib.nullcontext