Python star symbol in a loop

Question

I am using CPython and I saw in one example file with a star symbol. Could you give an explanation what in this context the * symbol means? Here the pointsets is a numpy array that comes from pybind11, because it is an output of C++ code.

Does the Point(*point) has something to do with the pointers in C++?

polylines = []
for points in pointsets:
    points = [Point(*point) for point in points]
    polyline = Polyline(points)
    polylines.append(polyline)

Does this answer your question? [What does the star and doublestar operator mean in a function call?](https://stackoverflow.com/questions/2921847/what-does-the-star-and-doublestar-operator-mean-in-a-function-call) — Passerby, Jan 07 '22 at 12:19
Possible yes, can you confirm that in this loops the start has nothing to do with the C++ code? Just unpacking of positional variables. — PetrasVestartasEPFL, Jan 07 '22 at 12:20

Tibebes. M · Accepted Answer · 2022-01-07T12:33:09.157

2

It's called unpacking operator. Here is what's written in the docs:

An asterisk * denotes iterable unpacking. Its operand must be an iterable. The iterable is expanded into a sequence of items, which are included in the new tuple, list, or set, at the site of the unpacking.

It is much like the "..." operator from Javascript ES6. (the spread operator)

https://docs.python.org/3/reference/expressions.html#expression-lists

edited Jan 07 '22 at 12:33

answered Jan 07 '22 at 12:22

Tibebes. M

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Thank you this is what I was searching for. – PetrasVestartasEPFL Jan 07 '22 at 12:24
@PetrasVestartasEPFL glad to help! consider upvoting/accepting it as an answer. – Tibebes. M Jan 07 '22 at 12:34

Python star symbol in a loop

1 Answers1