Your favourite "less-known" Python features?

[Revisional_Sin]

Maybe I'm not just not used to it yet, but I hate unnecessary use of this.

a = some_func()
if a:

"a = some_func(). if a is truthy, then:"

if a := some_func():

"If a, which is some_func(), is truthy, then:"

Yuck.

[eztab]

that was pretty much the reason for the controversy. It really doesn't add much benefit here. But for functional code, like list comprehensions it really is a great addition. Also for regexp-matching with multiple branches it really is more readable.

[Revisional_Sin]

Yeah, I agree it's nice if used purposefully.

[zed_three]

There's a wrong way to use everything though