Python Lists

In real life, we often need to keep track of multiple items together. For example, a list of groceries, names of your friends, or favorite movies.

In Python, we use something called a list to store many items in one place.

What is a List?

A list is a collection of items. These items are stored in a specific order, and you can add, change, or remove items whenever you want.

Think of it like a shopping list you can edit!

How to Create a List

You can create a list by putting items inside square brackets [ ], separated by commas.

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

What Does This Mean?

• fruits is the name of the list.
• It contains 3 items: "apple", "banana", and "cherry".
• The items are stored in the order you write them.

Where Are Lists Used?

Lists are used everywhere when you need to store multiple values together. Some examples:

• Shopping lists
• Student names in a class
• Scores in a game
• Tasks in a to-do app

Nature of Lists

• Lists can hold different types of items (strings, numbers, even other lists!).
• Lists are ordered. This means the position of each item is important.
• Lists can be changed (we can add, remove, or update items).

Basic List Operations (CRUD)

Create

Creating a new list:

colors = ["red", "green", "blue"]

Read (Access Items)

We can read items by their position (called an index). Remember, counting starts from 0!

print(colors[0])

Output:

red

Here, colors[0] gives us the first item, which is "red".

Update (Change Items)

We can change an item in the list:

colors[1] = "yellow"
print(colors)

Output:

['red', 'yellow', 'blue']

We changed the second item ("green") to "yellow".

Delete (Remove Items)

We can remove items from the list using del:

del colors[2]
print(colors)

Output:

['red', 'yellow']

We deleted the third item ("blue"). Now only two colors are left.

More Useful List Tricks

Adding Items

Use append() to add a new item at the end:

colors.append("purple")
print(colors)

Output:

['red', 'yellow', 'purple']

Checking the Length of a List

Use len() to find how many items are in the list:

print(len(colors))

Output:

3

Summary

• A list holds multiple items in one place.
• Items are ordered and can be changed.
• You can create, read, update, and delete items easily.

Now that you know lists, you're ready to start managing collections of data in your Python programs!