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Lesson 3: Lists and Loops
BartPowers1 (4)

Lesson 3: Lists and Loops

A list is another way to store things, but it can hold a lot of things. Lets look at a few examples:

  • Lets say our parents want to make cookies and we need to create a shopping list
  • Think of the things you need to make cookies: Milk, eggs, sugar, chocolate chips, flour.
  • See how we wrote that sentence above? we separated each item we need with a comma. Writing code is very similar:
shoppingList = ["Milk", "Eggs", "Sugar", "Chocolate chips", "Flour"]

Lets print that list out…


That will print out:

['Milk', 'Eggs', 'Sugar', 'Chocolate chips', 'Flour']

Now lets find out how to print specific items in our shopping list. Each item in our list has its own index. An index is a number used to get that item from the list. Lists always start with the number 0.

   0       1        2             3             4
['Milk', 'Eggs', 'Sugar', 'Chocolate chips', 'Flour']

So to print out the first item from our shopping list, we would write: print(shoppingList[0]) which would print Milk .

  • We access the items by using the name of our list shoppingList and putting the index of the number we want inside [ ]
  • So to print out Sugar we would do print(shoppingList[2])
    Now how would you get our program to print out Flour ?

Answer: To print out Flour we would do print(shoppingList[4])

Lets practice and teach you about Loops!

  • A loop is a way for the program to do something over, and over, and over again
  • We use loops to do repetitive tasks for us so we don’t have to
  • Take a look at the code below.
  • Add some of your favorite movies to the favoriteMovies list
    Let’s show you your first loop
for movie in favoriteMovies:
    print(movie + " is one of my favorite movies")

This loop says … for each movie in our favoriteMovies list we want our computer to say “_ is one of my favorite movies”

Press the play button to see what happens!

Previous Lesson - Lesson 2: Variables

Bookie0 (5957)

Instead of making several posts with different lessons, try to join/concatenate all your posts to make one big tutorial! :D

IntellectualGuy (668)

@Bookie0 Yes, this would be called cycle squeezing @BartPowers1

bp1234 (0)

@Bookie0 that would be great, how do you do that? Honestly I only split it up here because I can't get the code editors to work on medium

If someone tries to fork and edit it online in that article it throws an error