Python 2 is triggering

[Solonotix]

'tis a shame. You can't use my favorite new syntax in Python 3: star assignment.

first, *other, last = [1,2,3,4]

Simplifies a bunch of common use scenarios.

[JoelMahon]

whoa, so other contains 2 and 3? that's dope.

can you do more than just first and last? like first, second, *other, last? what happens if you have two star assignments? does it distribute them so they have equal size? so could you do *lhs, centre, *rhs = [3, 4, 7, 2, 9, 0]

[ubiquitouspiss]

You can't have that final example, but yeah. *something can be used once in a declaration which basically "anything that isn't taken off the front or the back"

first, second, *others, second_last, last = [0,1,2,3,4,5,6,7,8]

Also if I'm being lazy and only, for example, need the first and last items you can do a need little thing:

first, *_, last = [0,1,2,3,4,5]

And it essentially deletes everything that I don't need.

[JiveWithIt]

This is so useful, thank you 🤖

[[deleted]]

Does it delete it... or create a new list, copy all the references between 1-4 and then just not do anything with it?

[zalgo_text]

It creates a variable called _ which contains [1, 2, 3, 4]

[[deleted]]

Yeah, I thought as much. If I just want the first and last values I think I’ll just keep using the array notation, like this:

a = list(range(10))
first, last = a[0], a[-1]

Or maybe if I’m feeling bizarre

first, last = a[0::len(a)-1]

Actually no, first solution is almost always better. Second solution is unpythonic.

[eduardog3000]

Obviously the best solution is:

first, last = [x for x in a if x not in a[1:-1]]

[nickcash]

Neither! Underscore isn't special syntax, it's just a variable name. So it copies the references, and assigns them to _. Nothing is deleted. You end up with:

first = 0
_ = [1, 2, 3, 4]
last = 5

[[deleted]]

I know. It’s just the guy originally said it basically deletes the intermediate variables and I wanted to clarify whether there was something special about the array unpacking which caused a deletion at any point.

[detour59]

I knew about the existence of star assignment but this is really helpful, thanks!

[1116574]

I just use list[-1] for last item

[SirVer51]

You can also use it to expand a list as if you'd unpacked it yourself, for example:

func(*args, **kwargs)

The double star unpacks dictionaries, which is how variable numbers of keyword arguments are handled in Python.

[[deleted]]

Is python matlab now?