What are “named tuples” in Python?

Question

Reading the changes in Python 3.1, I found something... unexpected:

The sys.version_info tuple is now a named tuple:

Answer 1

Another way (a new way) to use named tuple is using NamedTuple from typing package: Type hints in namedtuple

Let's use the example of the top answer in this post to see how to use it.

(1) Before using the named tuple, the code is like this:

pt1 = (1.0, 5.0)
pt2 = (2.5, 1.5)

from math import sqrt
line_length = sqrt((pt1[0]-pt2[0])**2 + (pt1[1]-pt2[1])**2)
print(line_length)

(2) Now we use the named tuple

from typing import NamedTuple, Number

inherit the NamedTuple class and define the variable name in the new class. test is the name of the class.

class test(NamedTuple):
x: Number
y: Number

create instances from the class and assign values to them

pt1 = test(1.0, 5.0)   # x is 1.0, and y is 5.0. The order matters
pt2 = test(2.5, 1.5)

use the variables from the instances to calculate

line_length = sqrt((pt1.x-pt2.x)**2 + (pt1.y-pt2.y)**2)
print(line_length)