Learn Python the Hard Way: A Deceptively Simple Introduction to the Terrifyingly Beautiful World of Computers and Data Science, 5th Edition

Exercise 19

Functions and Variables

You’re now going to combine functions with what you know of variables from previous exercises. As you know, a variable gives a piece of data a name so you can use it in your program. If you have this code:

1   x = 10

then you created a piece of data named x that is equal to the number 10.

You also know that you can define (create) functions with parameters like this:

Click here to view code image

1   def print_one(arg1):
2       print(f"arg1: {arg1}")

The parameter arg1 is a variable similar to the x before, except it’s created for you when you call the function like this:

1   print_one("First!")

In Exercise 18, you learned how Python runs functions when you call them, but what happens if you did this:

1   y = "First!" ...