Sequences

Sequences are special iterables, that has a linear order. As opposed to a set that is iterable, but has no order.

Array

The mutable sequence.

Tuple

The immutable sequence. Some usecases:

A record:

>>> name, age, _ = ('Alice', 30, 'Software engineer')
>>> name
'Alice'
>>> age
30

A list that never changes:

>>> suits = ('diamonds', 'clubs', 'hearts', 'spades')
>>> suits.
suits.count(  suits.index(

But it’s not transitive, references might point to mutable objects.

Named tuple

Tuple factory function. Create tuples that look like a dict: look up members using their names instead of indexes. When unpacking a record, we may mix up the order.

Unpacking iterables

Unpacking:

>>> name, age, *_ = ('Alice', 30, 'Software engineer', 'Budapest')

Pattern matching with sequences

Python 3.10!

https://github.com/gvanrossum/patma/tree/3ece6444ef70122876fd9f0099eb9490a2d630df

match points:
case []:
    print("No points")
case [Point(0, 0)]:
    print("The origin")
case [Point(x, y)]:
    print(f"Single point {x}, {y}")
case [Point(0, y1), Point(0, y2)]:
    print(f"Two on the Y axis at {y1}, {y2}")
case _:
    print("Something else")

#python