Python

I use python a lot to automate various file management on my computer, so

@contextmanager
def cd(newdir) 
    prevdir = os.getcwd()
    os.chdir(os.path.expanduser(newdir)
    try:
        yield
    finally:
        os.chdir(prevdir)

is my most reused function as it allows me write

with cd(newdir) 
    #stuff

So I'd definitely go with contextmanager/yield as my favourite syntax sugar.

Generators probably. It's the one thing i genuinely miss about python when i work in rust.

I come from the school of thought that programs should look like what they do. So I have mixed felling about the complexity increase in Python. Also about those pushing types.

That said the subrange notation is one of the most important. I have used everything you mentioned in the appropriate places though. I find myself using list comprehensions and also the format method more often these days.

Dataclasses and __post_init__, what should have been the default.

Context managers primarily but quickly followed up by decorators. I primarily develop in Go nowadays and miss them dearly.

I have to go with type hints. Even when the project doesn't have any static type check in place, they help reason about the code.

The recent addition of match case has been a blast for me.

Another useful one is static methods.

Decorators are one of most useful features I'm using most frequently.

Yeah, I'm just learning about decorators in classes, and they're super cool!

decorators and the match statement for pattern matching. Finally have a switch statement, even if Guido didn't want it. It's just an advanced switch statement.

List comprehensions, dict comprehensions, set comprehensions, and generator expressions. They just make it so fast and easy to transform data.

Also just generators in general. I really like how they save unnecessary computation (when used prudently of course!).

And I'm also a big fan of list indexing, especially how you can extract the last three elements of a list using l[-3:]. Very elegant syntax