3.5 Tuple basics

Learning objectives

By the end of this section you should be able to

Describe the features and benefits of a tuple.
Develop a program that creates and uses a tuple successfully.
Identify and discuss the mutability of a tuple.

Creating tuples and accessing elements

A tuple is a sequence of comma separated values that can contain elements of different types. A tuple must be created with commas between values, and conventionally the sequence is surrounded by parentheses. Each element is accessed by index, starting with the first element at index 0.

tuple_1 = (2, 3, 4) print(f'tuple_1: {tuple_1}') print(tuple_1[1]) print data_13 = ('Aimee Perry', 96, [94, 100, 97, 93]) print(f'data_13: {data_13}') print(data_13[2]) tuple_1: (2, 3, 4) 3 data_13: ('Aimee Perry', 96, [94, 100, 97, 93]) [94, 100, 97, 93]

Tuple properties

How do tuples compare to lists? Tuples are ordered and allow duplicates, like lists, but have different mutability. An immutable object cannot be modified after creation. A mutable object can be modified after creation. Tuples are immutable, whereas lists are mutable.

Note

Creating a tuple from a list

Suppose a programmer wants to create a tuple from a list to prevent future changes. The tuple function creates a tuple from an object like a list. Ex: my_tuple = tuple(my_list) creates a tuple from the list my_list. Update the program below to create a tuple final_grades from the list grades.

grades = [68, 77, 81, 73]
grades[0] += 5

print(f'final_grades: {final_grades} is a {type(final_grades)}')

Note

Creating a tuple with user input

Write a program that reads in two strings and two integers from input and creates a tuple, my_data, with the four values.

Given input:

The output is:


    my_data: ('x', 'y', 15, 20)

# Read input and create my_data

print(f'my_data: {my_data}')