What is a List in Python?

Learn what lists are, how they work, and how to use them in your Python code. …

Learn what lists are, how they work, and how to use them in your Python code.

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Definition of the Concept

In Python, a list is a collection of items that can be of any data type, including strings, integers, floats, and other lists. Lists are denoted by square brackets [] and are used to store multiple values in a single variable.

Step-by-Step Explanation

Here’s a step-by-step breakdown of how lists work:

1. Creating a List: To create a list, you enclose a series of items in square brackets []. For example:

my_list = [1, 2, 3, 4, 5]

This creates a list called my_list containing the integers 1 through 5.

2. Accessing List Elements: To access an element in a list, you use its index (position) within the square brackets. Indexing starts at 0, so the first element is at index 0.

print(my_list[0])  # Output: 1

In this example, we print the first element of my_list, which is 1.

3. Modifying List Elements: To modify an element in a list, you assign a new value to its index using the assignment operator =.

my_list[0] = 'apple'
print(my_list)  # Output: ['apple', 2, 3, 4, 5]

Here, we replace the first element of my_list with the string 'apple'.

4. Adding Elements to a List: To add an element to the end of a list, you use the append() method.

my_list.append('banana')
print(my_list)  # Output: ['apple', 2, 3, 4, 5, 'banana']

In this example, we append the string 'banana' to the end of my_list.

5. Removing Elements from a List: To remove an element from a list, you use the remove() method or slice notation.

my_list.remove('apple')
print(my_list)  # Output: [2, 3, 4, 5, 'banana']

Here, we remove the string 'apple' from my_list.

Code Snippets

Creating a List

my_list = [1, 2, 3, 4, 5]
print(my_list)  # Output: [1, 2, 3, 4, 5]

Accessing List Elements

print(my_list[0])  # Output: 1
print(my_list[-1])  # Output: 5 (negative indexing starts from the end)

Modifying List Elements

my_list[0] = 'apple'
print(my_list)  # Output: ['apple', 2, 3, 4, 5]

Adding Elements to a List

my_list.append('banana')
print(my_list)  # Output: ['apple', 2, 3, 4, 5, 'banana']

Removing Elements from a List

my_list.remove('apple')
print(my_list)  # Output: [2, 3, 4, 5, 'banana']

Conclusion

In this article, we’ve explored the concept of lists in Python. We’ve created lists, accessed and modified elements, added new elements, and removed existing ones. With these fundamental skills, you’ll be able to tackle a wide range of problems in your Python code.

Additional Resources

• Python Documentation: Lists
• W3Schools: Python Tutorial - Lists