🐍Python Lists (Data Structures) 📦

🔹 1. What is a List?

A list is a sequence of values (items). They are ordered, changeable (mutable), and allow duplicate members. Defined by square brackets [].

Example:

my_list = ["apple", 3.14, True, 100]
print(my_list)

Output: ['apple', 3.14, True, 100]

🔹 2. Accessing List Items

Items are accessed by their index, which starts at 0 for the first item.

Example:

fruits = ["apple", "banana", "cherry"]
print(fruits[0]) # First item
print(fruits[2]) # Third item
print(fruits[-1]) # Last item

Output:
apple
cherry
cherry

🔹 3. Modifying List Items

You can change an item by referring to its index.

Example:

colors = ["red", "green", "blue"]
colors[1] = "yellow" # Change 'green' to 'yellow'
print(colors)

Output: ['red', 'yellow', 'blue']

🔹 4. Adding Items to a List

• .append(): Adds an item to the end of the list.
• .insert(index, item): Adds an item at a specific index.

Example:

names = ["Alice", "Bob"]
names.append("Charlie") # Add to end
names.insert(0, "David") # Add at the beginning
print(names)

Output: ['David', 'Alice', 'Bob', 'Charlie']

🔹 5. Removing Items from a List

• .remove(item): Removes the first occurrence of a specified item.
• .pop(index): Removes (and returns) the item at a specified index (or the last item if no index is given).
• del list[index]: Deletes the item at a specific index.

Example:

numbers = [10, 20, 30, 20, 40]
numbers.remove(20) # Removes first '20'
del numbers[0]     # Removes '10'
print(numbers)

Output: [30, 20, 40]

🎯 Today's Goal(What you should do)

✔️ Understand what lists are and how to create them
✔️ Access items using indexing
✔️ Modify, add, and remove items from lists