Practical Programming, 3rd Edition

Storing Data Using Tuples

Lists aren’t the only kind of ordered sequence in Python. You’ve already learned about one of the others: strings (see Chapter 4, ​Working with Text​). Formally, a string is an immutable sequence of characters. The characters in a string are ordered and a string can be indexed and sliced like a list to create new strings:

>>> rock = 'anthracite'
>>> rock[9]
'e'
>>> rock[0:3]
'ant'
>>> rock[-5:]
'acite'
>>> for character in rock[:5]:
...     print(character)
...

a
n
t
h
r

Python also has an immutable sequence type called a tuple. Tuples are written using parentheses instead of brackets; like strings and lists, they can be subscripted, sliced, and ...