Lab 3, Part 1: print, return, and None

Summary

• print causes characters to be displayed in the shell (the bottom pane of your Thonny window)
• return specifies the result of the function invocation
• a function without an explicit return statement returns the special None value (which Python typically does not print)

Here is the worksheet as a google doc Open the document, then File -> Make a Copy. Then you can edit your copy with your answers.

Examine the following functions. Which are fruitful and which are None functions?

def hello(x):
    print('--', x, '--')

def square(x):
    return x * x

def showSquare(num):
    print('The argument of square is ' + str(num))
    return square(num)

Predict the outcome of the invocations below:

>>> hello('froggy')

>>> print(hello('bunny'))

>>> square(3) + square(4)

>>> square(square(3))

>>> showSquare(5)

>>> showSquare(3) + showSquare(4)

>>> hello('frog') + hello('toad')

Table of Contents

• Lab 3 Home
• Part 1: Poems
• Part 2: Exercises
• Bonus Part: Turtle cake baking
• Knowledge Check