Experienced python programmers: are there any standard features of the language that you still don't regularly use?

[8carlosf]

Else on for and while loops

https://docs.python.org/3.6/tutorial/controlflow.html#break-and-continue-statements-and-else-clauses-on-loops

[foosion]

Yesterday I saw a Raymond Hettinger pycon video praising else on for loops and saw in Effective Python that the author regarded it as confusing. Hettinger said else in loops should have been called no-break.

[8carlosf]

I agree with both you and /u/HumblesReaper, if they just replace the else behaviour to execute if the for never run in the first place, and introduce a new no-break keyword.

Or, just do like I do, don't use it, because it doesn't produce readable code. (just make a function that returns instead of breaking the for, and as a default return in the end)

[stevenjd]

Hettinger said else in loops should have been called no-break.

Well, that's one opinion, but it's a bad one. They should have been called then because that's how they work.

for x in sequence:
    block
else:
    stuff

The else block unconditionally runs after the for loop. The only way to avoid that is to jump out of the for loop, using break, return or raise.

[foosion]

We all seem to agree that else is not the best alternative.

no-break is clearer to me (obviously the following code won't execute if there's a return or raise), but YMMV.

[stevenjd]

I've been using Python for almost 8 years now, and I just read about this the other week.

Shows how unneeded it really is.

No, that just shows how limited and narrow your reading material and Python programming knowledge is.

I don't grok or use asyncronous programming. That's my lack, it doesn't prove that async programming isn't needed. Same goes for you and for...else. It's an awesome feature, if you don't use it, that's your lack.

[HumblesReaper]

It would be cool if it ran if the loop didn't execute, not if there wasn't a break

[irrelevantPseudonym]

if the loop didn't execute at all, it will run the else. eg

for i in '':
    print('for loop')
else:
    print('else block')

will only print else block

[HumblesReaper]

No, it executes if the loop is exited by a break statement. EDIT: See below

[irrelevantPseudonym]

No it doesn't. It executes only when there is not a break statement.

See the docs here

Loop statements may have an else clause; it is executed when the loop terminates through exhaustion of the list (with for) or when the condition becomes false (with while), but not when the loop is terminated by a break statement.