Data Transformer

Part of the Logic & Flow section of Coddy's Python journey — lesson 78 of 78.

Challenge

Hard

Create a function named transform_dataset that processes a list of student records for analysis.

Each record is a dictionary containing:

student_id: A unique identifier for the student
grades: A list of numerical grades
subjects: A list of subjects the student is taking

Your function should:

Calculate the average grade for each student
Only include students who have all grades above 70 (qualified students) - you should use Python's all() function to check this condition
Create a summary of the subjects taken by qualified students, counting how many qualified students take each subject
Return a dictionary with two keys:
- qualified_students: A dictionary mapping student IDs to their average grade (rounded to 2 decimal places)
- subject_summary: A dictionary mapping subjects to the count of qualified students taking that subject

Note: The all() function in Python returns True only if all elements in the iterable are true. For example, all(grade > 70 for grade in grades) will return True only if every grade is above 70.

Example Input:

[
    {
        "student_id": "S123", 
        "grades": [88, 92, 85], 
        "subjects": ["Math", "Science", "History"]
    },
    {
        "student_id": "S124", 
        "grades": [65, 95, 80], 
        "subjects": ["Math", "Science", "English"]
    },
    {
        "student_id": "S125", 
        "grades": [91, 89, 92], 
        "subjects": ["Math", "Physics", "History"]
    }
]

Example Output:

{
    'qualified_students': {'S123': 88.33, 'S125': 90.67}, 
    'subject_summary': {'Math': 2, 'Science': 1, 'History': 2, 'Physics': 1}
}

Try it yourself

def transform_dataset(data):
    # Your solution here
    
    # Step 1: Calculate average grade for each student and filter qualified students
    # (students with all grades above 70)
    
    # Step 2: Create a summary of subjects taken by qualified students
    
    # Step 3: Return the final dictionary with qualified_students and subject_summary
    pass