Functions

Sometimes we have some code that we might want to run at multiple points in our program. In this situation, we put that code into a function, which we can then call again and again.

Example 1

For example, maybe we want to print the same greeting for many different people. Lets' write a function to handle that.

Add the following to functions.py:

# functions.py

def generate_greeting(name):
    print('Hello, ' + name)

What happens when you run your code? Nothing (hopefully).

That’s because the code inside our function does not run until we call the function.

Add the following to functions.py:

# functions.py

def generate_greeting(name):
    print('Hello, ' + name)

+generate_greeting('Myrtle')

Now when you run the code, you should see the print statement appear in the console.

But the point of writing a function is being able to reuse the code. Let’s try calling our function more than once, to handle greeting multiple names.

Add the following to functions.py:

# functions.py

def generate_greeting(name):
    print('Hello, ' + name)

generate_greeting('Myrtle')
+generate_greeting('Shelley')
+generate_greeting('Sheldon')
+generate_greeting('Enzo')

Now when you run the code, you should see multiple print statements appear in the console.

The names that we are passing to the function are called parameters. When we pass Enzo to the function, it becomes the value of name, which we can then use in our function.

Example 2

Let’s see another example.

Maybe there is a equation that we want to reuse. For example, let’s write a function that converts temperatures given in fahrenheit to celsius.

Add the following to functions.py:

# functions.py

def convert_f_to_c(temp_in_f):
    print(temp_in_f - 32) * (5/9)

Challenges

Back to the game!

How did you get here?

• Myrtle
• Birds
• World

p.s. this is Enzo: