Is arr len the preferred way to get the length of an array in Python

Question

In Python, is the following the only way to get the number of elements?

arr.__len__()

If so, why the strange syntax?

Answer 1

my_list = [1,2,3,4,5,6,7]
len(my_list)
# 7
The same works for tuples:

my_tuple = (1,2,3,4,5,6,7)
len(my_tuple)
# 7
And strings, which are really just arrays of characters:

my_string = 'hello world'
len(my_string)