September 19: Functions

Learning Objectives

After today's class, you should be able to:

  • Explain the flow of execution from one function to another.
  • Describe the syntax of function definitions and function calls.
  • Write short functions that have parameters and return values.

Lesson Outline

Class Activity: 20 min

Mini Lecture: 20 min

Recap of Return Examples 5min 

# Example 1: No return statement

def greeting():
    print("Have a nice day!\n")


# Example 2: One return statement

def time_str(hour, minute):
    if hour < 12:
        ampm = "AM"
    else:
        ampm = "PM"
        hour -= 12
    if hour == 0:
        hour = 12
    return f"{hour}:{minute:02d} {ampm}"


# Example 3: Multiple return statements

def analyze(number):
    if number == 0:
        return "Zero!"
    if number > 0:
        return "Positive"
    return "Negative"


# Example 4: Multiple return values

def stats(grades):
    avg = sum(grades) / len(grades)
    return min(grades), avg, max(grades)


if __name__ == "__main__":
    print("1:", greeting())
    print("2:", time_str(12, 5))
    print("3:", analyze(-1))
    print("4:", stats([95, 71, 100, 88]))
Class Activity 2: 30 min

Your To-Do List

Due Wednesday September 20th at 11pm

  • Submit HW 4 through Canvas and check out the Help page. Remember the attribution statement

Prepare for Quiz 2A

  • Thursday, beginning of class, 25 minutes, in EnGeo 2204.
  • Two parts: concepts and programming (will use lab machine account, canvas and gradescope)
  • Study chapters 3 and 4: both reading and activities
  • Review class activities
  • Review homework programming assignments