Is it possible to write a PEP 8 compliant, one-line, conditional expression that can do nothing?

Let’s say I have the following code

if condition_met:
    do_something()

Where I call do_something for a specific condition, but otherwise do nothing. I could condense it to one line with the following

if condition_met: do_something()

But that wouldn’t be PEP 8 compliant. I was hoping something like the following would work.

do_something() if condition_met

But its a syntax error unfortunately. I tried the next, fairly silly, one-liner, but it too is a syntax error even though it’s multi-line equivalent is valid.

do_something() if condition_met else pass  # syntax error
...
if condition_met:
    do_something()
else:
    pass  # valid syntax

I’ve came up with the following one line expression that is PEP-8 compliant, or at least makes flake8 happy.

do_something() if condition_met else None

But the above isn’t very pythonic and the multi-line equivalent makes even less sense than the one using pass. Is there a way to do nothing in a one-line expression while still being PEP 8 compliant?

>Solution :

You could do:

 condition_met and do_something()

The short-circuiting behavior of and means do_something() is only invoked if condition_met is truthy (the result of the expression would be whatever do_something() returned in that case).

I’d personally recommend sticking to the two-liner, or even violating PEP8 and putting the two-liner on one line if you really hate two-lining it. Using and for flow control without the result of the whole expression being used is more ugly/confusing than the straightforward solution.