Tuples

Tuples#

Introduction to Tuples#

A tuple is an ordered collection of objects, similar to a list. However, tuples have some distinct characteristics that make them useful in specific scenarios.

Defining a Tuple#

Tuples are defined using parentheses (round brackets) () instead of the square brackets [] used for lists.

noble_gases = ('helium', 'neon', 'argon', 'krypton', 'xenon', 'radon')

We can check noble_gases is a tuple, using the type() function:

type(noble_gases)

tuple

Accessing Tuple elements#

Like lists, we can use the index notation to access particular elements in a tuple.

print(noble_gases[0])

helium

print(noble_gases[-1])

radon

Tuples are Immutable#

The main difference between a tuple and a list is that tuples are immutable: once created, they cannot be altered.

noble_gases[0] = 'Helium'

---------------------------------------------------------------------------
TypeError                                 Traceback (most recent call last)
Cell In[5], line 1
----> 1 noble_gases[0] = 'Helium'

TypeError: 'tuple' object does not support item assignment

However, you can still concatenate tuples:

new_noble_gases = noble_gases + ('oganesson',)
print(new_noble_gases)

('helium', 'neon', 'argon', 'krypton', 'xenon', 'radon', 'oganesson')

Note the trailing comma in ('oganesson',) — this is necessary for Python to recognise this as a tuple with one element.

Tuple Properties#

  1. Heterogeneous Data: Tuples can contain items of different data types.

my_tuple = (0, 'a', 2.3)
print(my_tuple)

(0, 'a', 2.3)

  1. Conversion: You can convert a tuple to a list and vice versa:

my_list = list(my_tuple)
print(my_list)

[0, 'a', 2.3]

Tuples vs Lists: When to Use Each#

Python provides both tuples and lists to cater to different programming needs and scenarios.

Key Differences#

  1. Mutability:

    • Lists are mutable (can be changed after creation).

    • Tuples are immutable (cannot be changed after creation).

  2. Syntax:

    • Lists use square brackets: [1, 2, 3].

    • Tuples use round brackets: (1, 2, 3).

  3. Performance:

    • Tuples are generally more memory efficient and faster to process.

Advantages of Tuples#

  1. Data Integrity: Immutability prevents accidental modifications.

  2. Debugging: If you try to change a tuple, Python will raise an error, helping catch bugs early.

  3. Guaranteed Consistency: The contents of a tuple remain the same throughout your code.

When to Choose Tuples#

  • Representing fixed collections of data (e.g., RGB color values).

  • Returning multiple values from a function.

  • When you want to ensure data doesn’t change accidentally.

  • As dictionary keys (when needed).

When to Choose Lists#

  • When you need a collection that will change size.

  • When you’ll frequently modify individual elements.

  • When you need list-specific methods (e.g., sort(), append()).

Conclusion#

In general, unless you know that you are going to want to do something with your data that you can only do with a list, it is often a good idea to use a tuple instead. This practice can lead to more efficient and less error-prone code. However, if you’re unsure or need the flexibility, starting with a list is often a safe choice. As you gain experience, you’ll develop an intuition for when each is most appropriate.