Lists and Loops

Today, we'll dive into lists in Python. A list is an ordered collection of items. Can anyone tell me how we define a list in Python?

Is it with square brackets?

Exactly, great! We create a list with square brackets. For example, fruits = ['apple', 'banana', 'cherry']. Now, can anyone tell me what happens if we want to add more fruits?

We can use the append() method?

Correct! You can add to the list dynamically using fruits.append('orange'). Lists are very flexible! Let’s see what else we can do with them.

Now that we know how to create lists, let's talk about loops. Who can explain what a loop does?

It repeats a block of code several times?

Exactly! In Python, we often use a 'for' loop to iterate through list items. For instance, for fruit in fruits: print(fruit). This will print each fruit in the list. Can anyone show me what print(fruit.upper()) does?

It will print each fruit in uppercase!

Great! That's how we can manipulate list items using loops. Remember, loops can enhance our ability to analyze large datasets.

Now let’s apply our knowledge. If I have a list of scores: scores = [85, 90, 78], how could I calculate the average score?

We could sum them and divide by the number of scores?

Yes! We can use a loop to do that: total = 0; for score in scores: total += score, and then divide by len(scores). This is a practical example of how lists and loops work together in coding!