Question

What you're creating

Using a case statement, create a function that accepts a letter grade and returns a minimum score to achieve that grade.

How you'll do it

You learned sequence structure, statements executed in order, then selection statements with if statements, then looping statements. In some languages, there is a case selection statements, sometimes called switch/case.

In Python, you can write your own case statement using a function and a dictionary.

In this assignment you will write a function switch_average that accepts a letter grade { A, B, C, D, F } and returns the correcting numeric average { 90, 80, 70, 60, 50 }, respectively.

In Module8 project

• Create a file assign_average.py with the unimplemented switch_average() function.
• Create a file test_assign_average.py
  • Write a function to test A (and a) return value
  • Write functions for the other 4 keys
  • Write function to test if a non-key is passed
    • What do you expect to happen? Should an exception be raised in the switch? How should you handle the case of no key found?
  • Run the tests and see them fail
  • Begin the implementation of switch_average.
    1. Make one test function pass for key value of 'A.
    2. Make the next test function pass for the next value.
    3. Repeat above step for each test until all are passing.

Notes/Hints

• This assignment can be achieved using a structure similar to the first case example given in class
• You must complete this using case statements even though it could be done using if/elif statements
• Your tests should cover all grades so there should be at least 5 of them

Answer 1

def switch_average(inp):
grades_dict = {'A':90, 'B':80, 'C':70, 'D':60, 'F':50 }
inp = inp.upper()
res = grades_dict.get(inp, 'Invalid Grade')
#get function for a dictionary will return value of key provided
# if the key is not found it will return the second argument in the fumction.
return res

print(switch_average('A'))
print(switch_average('a'))
print(switch_average('B'))
print(switch_average('b'))
print(switch_average('C'))
print(switch_average('c'))
print(switch_average('D'))
print(switch_average('d'))
print(switch_average('F'))
print(switch_average('f'))
print(switch_average('X'))
print(switch_average('x'))