Warmup

• Store in my_list a list of 5 items
• Store in partial_list a slice of my_list beginning at index 2 and stopping at index 4

Agenda

• Tomorow's Class is in Belk Gym

• Thursday class:

  • 3rd Block: Meet at Cone courtyard at 10:15
  • 4th Block: Meet at Cone courtyard at 12:20
  • We will walk together to Denny/Burson

• Mr. Lapinel absent tomorrow (Lesson 3.4 is on your own)

• Lesson 3.3 today

Due dates

• Python Essentials 1 Module 3 Quiz due Thursday
• Python Essentials 1 Module 3 Test due Friday
• Unit 3 Quiz 1 Friday (lists, tuples, dictionaries)

Lesson 3.3 – Lists: Iteration

What we’ll learn today

• How to loop through lists with for
• How to use in with lists
• Practical exercises combining loops + lists

Quick Review

• What is a list slice?
• Name two list methods from last class.

Looping Through Lists

• We can use a for loop to go through each element.

fruits = ["apple", "banana", "cherry"]
for fruit in fruits:
    print(fruit)

Try It

• Make a list of 5 animals.
• Write a for loop to print each one.

Using Indexes

• Sometimes you need the index too.

nums = [10, 20, 30]
for i in range(len(nums)):
    print(i, nums[i])

Class Question

• When would it be useful to loop by index instead of by value?

Membership Test with in

• Check if something is in the list.

colors = ["red", "green", "blue"]
if "red" in colors:
    print("Yes, red is here!")

Mini Practice

pets = ["dog", "cat", "fish"]
if "hamster" not in pets:
    print("Hamster not found")

• What will it print?

Loop + Condition

• We can mix loops with if-statements.

nums = [1, 2, 3, 4, 5]
for n in nums:
    if n % 2 == 0:
        print(n, "is even")

Mini Challenge

1. Make a list of numbers from 1 to 10.
2. Loop through them.
3. Print only the odd numbers.