Python - Tuples

Python tuple is immutable ordered collection which can have duplicates.

The difference between Python lists and tuples is that, lists are mutable (can be changed), whereas, tuples are immutable (cannot be changed).

Declaring tuples

even_numbers = (2, 4, 6)
print(even_numbers)

(2, 4, 6)

Declaring a tuple of mixed types

items = (2, "three", 2.3)
print(items)

(2, 'three', 2.3)

Using type() on a tuple

even_numbers = (2, 4, 6)
print(type(even_numbers))

<class 'tuple'>

Accessing Tuple elements

Tuples can be accessed via zero-based indexing:

even_numbers = (2, 4, 6)
print(even_numbers[0])
print(even_numbers[1])
print(even_numbers[2])

2
4
6

Accessing tuples from right side

even_numbers = (2, 4, 6)
print(even_numbers[-1])
print(even_numbers[-2])
print(even_numbers[-3])

6
4
2

Finding index of an element

alphas = ('a', 'b', 'c', 'd', 'e')
i = alphas.index('c')
print(i)

2

Finding index in sub-tuple

alphas = ('a', 'b', 'a', 'c', 'a')
i = alphas.index('a', 2) # from index 2
print(i)
i = alphas.index('a', 3, 5) # from index 3 to index 5
print(i)

2
4

ValueError

ValueError is raised if element does not exist when we use index() method:

alphas = ('a', 'b', 'c', 'd', 'e')
i = alphas.index('z')
print(i)

Traceback (most recent call last):
     i = alphas.index('z')
ValueError: tuple.index(x): x not in tuple

Getting length of a tuple

even_numbers = (2, 4, 6)
length = len(even_numbers)
print(length)

3

Trying to replace an element

Since tuples are immutable data structures, an error is thrown if we try to replace elements:

even_numbers = (2, 4, 6)
even_numbers[0] = 10
print(even_numbers)

Traceback (most recent call last):
     even_numbers[0] = 10
TypeError: 'tuple' object does not support item assignment

Tuples also do not support appending/inserting new elements, deleting elements by values or by index, clearing all elements (via clear()), sorting (via sort()), reversing order (via revers()) and copy (via copy()).

Removing whole tuple (removing from memory)

alphas = ('a', 'b', 'c', 'd', 'e')
#removing complete tuple (just like other objects via del)
del alphas
print(alphas)

Traceback (most recent call last):
     print(alphas)
NameError: name 'alphas' is not defined

Index error

If we try to access a tuple outside of it's index range:

even_numbers = (2, 4, 6)
even_numbers[3]=8
print(even_numbers)

Traceback (most recent call last):
     even_numbers[3]=8
TypeError: 'tuple' object does not support item assignment

Looping tuple

even_numbers = (2, 4, 6)
for x in even_numbers:
    print(x)

2
4
6

Looping by index

even_numbers = (2, 4, 6)
length = len(even_numbers)
for x in range(length):
    print(even_numbers[x])

2
4
6

Checking if an element exits in a tuple

alphas = ('a', 'b', 'c', 'd', 'e')
result = 'c' in alphas
print(result)

True

Finding frequency of an element

alphas = ('a', 'b', 'a', 'd', 'a')
i = alphas.count('a')
print(i)
# if element does not exist
i = alphas.count('z')
print(i)

3
0

Finding substrings

alphas = ('a', 'b', 'c', 'd', 'e')
print(alphas[1:3])
print(alphas[:2])
print(alphas[2:])

('b', 'c')
('a', 'b')
('c', 'd', 'e')

Example Project

Dependencies and Technologies Used:

• Python 3.10.2