How to handle both `with open(…)` and `sys.stdout` nicely?

Question

Often I need to output data either to file or, if file is not specified, to stdout. I use the following snippet:

if target:
    with open(target, \'w\') as h         


        

Answer 1

If it's fine that sys.stdout is closed after with body, you can also use patterns like this:

# Use stdout when target is "-"
with open(target, "w") if target != "-" else sys.stdout as f:
    f.write("hello world")

# Use stdout when target is falsy (None, empty string, ...)
with open(target, "w") if target else sys.stdout as f:
    f.write("hello world")

or even more generally:

with target if isinstance(target, io.IOBase) else open(target, "w") as f:
    f.write("hello world")