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

Okay, if we are getting into one-liner wars, here's:

(target and open(target, 'w') or sys.stdout).write(content)

I like Jacob's original example as long as context is only written in one place. It would be a problem if you end up re-opening the file for many writes. I think I would just make the decision once at the top of the script and let the system close the file on exit:

output = target and open(target, 'w') or sys.stdout
...
output.write('thing one\n')
...
output.write('thing two\n')

You could include your own exit handler if you think its more tidy

import atexit

def cleanup_output():
    global output
    if output is not sys.stdout:
        output.close()

atexit(cleanup_output)