5.17. Group Work: Functions

It is best to use a POGIL approach with the following. In POGIL students work in groups on activities and each member has an assigned role. For more information see https://cspogil.org/Home.

Note

If you work in a group, have only one member of the group fill in the answers on this page. You will be able to share your answers with the group at the bottom of the page.

Learning Objectives

Students will know and be able to do the following.

Content Objectives:

• Learn how to display a value in Python using print.

• Match terms for functions to their definitiions.

• Recognize common symbols (:, #), operators (+, -, /), and keywords (def, return) in Python.

Process Objectives:

• Modify code that includes function definitions and function calls

• Learn how to properly indent the body of a function

• Predict output from functions.

5.17.1. Print and Function Basics

Look at the code below and predict what it will print.

Run the Python code below and then answer the following questions.

Run the code below to see what it prints and then use it to answer the following questions.

# function definition def test(a, b = 2): print("Welcome") print("Learn the power of functions!") print(a + b) print(a - b) print(a * b) print(a / b) print(a // b) a = 5 % 2 return a # function definition def main(): print("Hello!") # function call print(test(3)) # function call main()

Note

You do not declare the type of a variable in Python. Python requires that all statements that are part of the body of a function must be indented. Use four spaces to indent.

5.17.2. Parts of a Function and Function Calls

Q-8: Click on all of the function headers in the code below.The first line in the function definition is the header.

# function definition
def print_message():
    print("Welcome to Python.")
    print("Learn the power of functions!")

# function definition
def main():
    print("Hello Programmer!")

    # function call
    print_message()

# function call
main()

Q-9: Click on all of the function names in the code below.The name of the function is after the def keyword and before the ().

# function definition
def print_message():
    print("Welcome to Python.")
    print("Learn the power of functions!")

# function definition
def main():
    print("Hello Programmer!")

    # function call
    print_message()

# function call
main()

Q-10: Drag each term to its definition Read the chapter on functions and try again.
• function definition
• All of the code that tells the program what to do when the function is executed. It includes the header and body.
• function header
• The first line of a function definition
• function body
• All of the lines in the function after the function header
• function call
• The name of the function followed by an argument list in ().
• function name
• Follows the def keyword and is before the list of arguments in ().

5.17.3. Writing Function Calls

Modify the code below to print the last two lines twice by only adding one line. That line can’t call the print function.

# function definition def print_message(): print("Welcome to Python.") print("Learn the power of functions!") # function definition def main(): print("Hello Programmer!") # function call print_message() # function call main()

Modify the code below to print “Hello Students” by adding one line and without calling the print function in that line.

# function definition def print_message(): print("Hello Students") # function definition def main(): # function call print_message()

5.17.4. Function Order

Q-13: Look at the Python code below. What do you think will happen when you run the following code?

Run the code below to see what happens when you try to call a function before it is defined.

# function call main() # function definition def print_message(): print("Welcome to Python.") print("Learn the power of functions!") # function definition def main(): print("Hello Programmer!") # function call print_message()

Note

Python processes the code in a file from left to right and from the first line to the last line. All functions must be defined before they are called.

Drag the blocks from the left and put them in the correct order on the right to define a function print_greeting that asks for your name and prints “Hello Name”. Then define a main function that calls print_greeting. Be sure to also call the main function. Note that you will have to indent the lines that are in the body of each function. Click the Check button to check your solution.

        def print_greeting():
---
def print_greeting() #paired
---
    name = input("What is your name?")
---
    print("Hello " + name)
---
def main():
---
Def main(): #paired
---
    print_greeting()
---
    print_greeting #paired
---
main()
        

5.17.5. Special Characters and Keywords

If you worked in a group, you can copy the answers from this page to the other group members. Select the group members below and click the button to share the answers.

The Submit Group button will submit the answer for each each question on this page for each member of your group. It also logs you as the official group submitter.

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