Loops

Remember lists? They look like this:

flowers = ['rose', 'violet', 'buttercup']

For now, let's just create a list and print it out. Our script will look like this:

flowers = ['rose', 'violet', 'buttercup']
print(flowers)

Run this script using your chosen method. You should see the list as output.

What if we want to print out each item in the list separately? For that, we'll need something called a loop:

flowers = ['rose', 'violet', 'buttercup']
# print(flowers)
for flower in flowers:
    print(flower)

What's happening here? This kind of loop is called a "for" loop, and tells Python: "for each item in the list, do something." Let's break it down:

for <variable name> in <list name>:
    <do something>

Indented code like this is known as a "code block." Python will run the code in the code block once for each item in the list. The code in the code block doesn't have to refer to the variable at all:

for flower in flowers:
    print("Yay! I'm in a loop!")

You can also perform more complicated operations:

prime_numbers = [2, 3, 5, 7, 11]

for num in prime_numbers:
    print('The square of %s is:' % num)
    print(num * num)