Now that you’ve learned how to use conditionals and loops, it’s time to give your programs more flexibility using lists. Python lists are ordered, changeable, and can hold anything — numbers, strings, or even other lists.

🔢 Step 1: Creating and Using Lists

Lists are created using square brackets [], and each item is separated by a comma.

groceries = ["eggs", "milk", "bread"]
print(groceries)

You can access specific items in the list using their index. Remember, Python starts counting at 0.

print(groceries[0])  # Output: eggs
print(groceries[2])  # Output: bread

✂️ Step 2: Indexing and Slicing

Indexing gets a single item. Slicing gets a range of items:

numbers = [10, 20, 30, 40, 50]

print(numbers[1:4])   # [20, 30, 40]
print(numbers[:3])    # [10, 20, 30]
print(numbers[2:])    # [30, 40, 50]

🔍 Note: The slice [1:4] includes index 1, 2, and 3 — but not 4. Python slicing is inclusive:exclusive.

🧱 Step 3: Building Lists Dynamically

You can start with an empty list and add items using append():

my_list = []
my_list.append("alpha")
my_list.append("beta")
print(my_list)  # ['alpha', 'beta']

🔁 Step 4: Looping Through Lists

You can use a for loop to go through each item in a list:

for item in groceries:
    print("Need to buy:", item)

🧮 Step 5: Using enumerate() for Index Tracking

If you need both the index and value, use enumerate():

for index, item in enumerate(groceries):
    print(f"{index}: {item}")

🔗 Step 6: Looping Two Lists at Once with zip()

Want to pair two lists together? zip() lets you loop through both at the same time:

names = ["Alice", "Bob", "Charlie"]
scores = [85, 92, 78]

for name, score in zip(names, scores):
    print(f"{name} scored {score}")

⏭️ Coming Up Next: Functions and Reusable Code

Next time we’ll build your own functions, pass in arguments, return results, and organize code better with reusability in mind.

Want a mini quiz or coding challenge before moving on? Just say the word.