Lists Basics

A list in Python is a collection of items that are ordered and changeable. Lists allow you to store multiple values in a single variable, making them a powerful tool for handling sequences of data.

Lists are defined using square brackets ([]) and can contain elements of different data types, including integers, strings, floats, and even other lists.

Creating Lists

To create a list in Python, simply enclose a series of elements in square brackets, separated by commas:

# Creating a list of numbers
numbers = [1, 2, 3, 4, 5]

# Creating a list of strings
fruits = ["apple", "banana", "cherry"]

# Creating a mixed-type list
mixed_list = [42, "hello", 3.14, True]

Accessing Elements in a List

Each element in a list has an index starting from 0. You can access elements using square brackets and the index:

fruits = ["apple", "banana", "cherry"]

print(fruits[0])  # Output: apple
print(fruits[1])  # Output: banana
print(fruits[2])  # Output: cherry

Negative Indexing

Python supports negative indexing, which allows you to access elements from the end of the list:

print(fruits[-1])  # Output: cherry
print(fruits[-2])  # Output: banana

Checking List Length

Use the len() function to find out how many elements a list contains:

print(len(fruits))  # Output: 3

Exercise: Try It Yourself!

Task 1: Creating and Accessing Lists

1. Create a list named colors that contains the colors: red, green, and blue.
2. Print the second item in the colors list.
3. Print the last item using negative indexing.

Task 2: List Length

Write a program that:

1. Creates a list of five favorite foods.
2. Prints the length of the list.

Next, we'll dive deeper into how to manipulate and modify lists in Python!