Usage of the Ternary Operator for Grade Determination

This code example demonstrates an advanced use of the ternary operator to determine grades based on scores. By leveraging nested ternary operators within a function, we can efficiently map numerical scores to letter grades.

This approach not only showcases the power of the ternary operator for handling multiple conditions but also highlights the elegance of Python’s list comprehensions for applying functions across collections. By the end of this example, you’ll see how these features work together to streamline the process of grade determination and output.

Code Example

# Function to determine the grade based on score
def determine_grade(score):
    return 'A' if score >= 90 else ('B' if score >= 80 else ('C' if score >= 70 else ('D' if score >= 60 else 'F')))

# List of scores
scores = [95, 82, 76, 59, 89, 99, 65, 73, 84, 91]

# Using list comprehension with ternary operator to assign grades
grades = [determine_grade(score) for score in scores]

# Printing the scores and their corresponding grades
for score, grade in zip(scores, grades):
    print(f"Score: {score}, Grade: {grade}")

Output

Score: 95, Grade: A
Score: 82, Grade: B
Score: 76, Grade: C
Score: 59, Grade: F
Score: 89, Grade: B
Score: 99, Grade: A
Score: 65, Grade: D
Score: 73, Grade: C
Score: 84, Grade: B
Score: 91, Grade: A

Code Explanation

Function to Determine Grade Based on Score

def determine_grade(score):
    return 'A' if score >= 90 else ('B' if score >= 80 else ('C' if score >= 70 else ('D' if score >= 60 else 'F')))

Explanation:

1. Function Definition:
   • def determine_grade(score): defines a function named determine_grade that takes one parameter, score.
2. Ternary Operator:
   • The ternary operator in Python is used for conditional expressions and is written as x if condition else y.
   • This function returns a grade based on the value of score using a nested ternary operator for multiple conditions.
3. Nested Ternary Operators:
   • The outermost ternary operator checks if score is greater than or equal to 90.
   • 'A' if score >= 90 else ...
   • If score is less than 90, it moves to the next condition:
   • 'B' if score >= 80 else ...
   • This nesting continues to check each subsequent range:
   • 'C' if score >= 70 else ...
   • Until it reaches the final condition for ‘D’ and ‘F’:
   • 'D' if score >= 60 else 'F'
   • This ensures that the appropriate grade is assigned based on the value of score.

List of Scores

scores = [95, 82, 76, 59, 89, 99, 65, 73, 84, 91]

Explanation:

• A list named scores is created, containing a series of integers representing different scores.

Using List Comprehension with Ternary Operator to Assign Grades

grades = [determine_grade(score) for score in scores]

Explanation:

1. List Comprehension:
   • List comprehensions provide a concise way to create lists.
   • The syntax [expression for item in iterable] is used here.
2. Calling the Function:
   • determine_grade(score) is called for each score in the scores list.
   • This means the determine_grade function is applied to each element in scores, resulting in a new list of grades.
3. Resulting List:
   • The result is a new list, grades, where each score from scores has been converted to its corresponding grade using the determine_grade function.

Printing the Scores and Their Corresponding Grades

for score, grade in zip(scores, grades):
    print(f"Score: {score}, Grade: {grade}")

Explanation:

1. zip Function:
   • The zip(scores, grades) function pairs each element in scores with the corresponding element in grades, creating an iterator of tuples.
   • Each tuple contains a score and its corresponding grade.
2. for Loop:
   • The for score, grade in zip(scores, grades) loop iterates over these tuples.
3. Print Statement:
   • print(f"Score: {score}, Grade: {grade}") prints each score and its corresponding grade in a formatted string.
   • The f before the string indicates an f-string, which allows for embedding expressions inside string literals using curly braces {}.

Summary

This code efficiently determines and prints grades for a list of scores using a function with nested ternary operators. The function determine_grade uses these nested ternary operators to evaluate the score and assign the appropriate grade. List comprehension applies this function to each score in the scores list, and the zip function pairs each score with its grade for easy printing.