Functions are ways for us to have a program remember code we already wrote and do it again. They're like recipes.

We can use functions to teach Tina how to do new things. We make a function by typing def, then the function name, a pair of parentheses (()), then a colon (:). Here's the beginning of a function named first_function:

def first_function():

After a funtion is defined, we can put code inside of it by indenting it. Indenting means having four spaces on the front:

def first_function():
    print "This line is indented 4 spaces!"

Once a function is defined, we can call it by typing its name and a pair of parentheses (()). Here's how we'll call our first_function():

first_function()

When we do this, everything inside the function will happen.

In this example, there's already a function called triangle() defined for you, and it is called one time. Call it one or more times and see what happens!

Ideas for modifying this program:

• Change what the triangle() says and Tina will do your new instructions.
• Try writing your own function and calling it as well!

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Thanks to Trinket.io for providing this assignment, part of their Hour of Python (opens new window) course.