dictionaryMaster_4.py

students = [
    {"name": "Bhoomi", "subject": "Math", "marks": 85},
    {"name": "Priya", "subject": "Physics", "marks": 92},
    {"name": "Aman", "subject": "Math", "marks": 78},
    {"name": "Riya", "subject": "Chemistry", "marks": 88},
    {"name": "Karan", "subject": "Physics", "marks": 65},
    {"name": "Neha", "subject": "Math", "marks": 91}
]

#grouping marks per subject
def marks_per_sub(students):
    groups = {}
    for s in students:
        subject = s["subject"]
        if subject not in groups:
            groups[subject] = []
        groups[subject].append(s["marks"])
    return groups

#calculating avg marks per subject 
groups = marks_per_sub(students)
def avg_marks_per_sub(groups):
    avg_result = {}

    for subjects,marks_list in groups.items():
        total = sum(marks_list)
        count = len(marks_list)
        avg_result[subjects] = round(total/count,2)

    return avg_result

#calculating students per subject 
def students_per_sub(students):
    groups = {}
    for s in students:
        subject = s["subject"]
        if subject not in groups:
            groups[subject] = []
        groups[subject].append((s["marks"],(s["name"])))
    return groups

stu_grp = students_per_sub(students)

#calculating topper per subject
def topper_per_sub(stu_grp):
    topper_dict = {}
    for subjects,records in stu_grp.items():
        top_marks, top_name = max(records)
        topper_dict[subjects] = (top_name,top_marks)

    return topper_dict

topper_dict = topper_per_sub(stu_grp)
#calculating overall topper
def overall_topper(topper_dict):
    return max(topper_dict.values(),key = lambda x: x[1])

#calculating subjet wise students
def subject_wise_students(students):
    groups = {}
    for s in students:
        subject = s["subject"]
        groups.setdefault(subject, []).append(s["name"])
    return groups


groups = marks_per_sub(students)
avg_per_subject = avg_marks_per_sub(groups)

stu_grp = students_per_sub(students)
toppers = topper_per_sub(stu_grp)

overall = overall_topper(toppers)

students_grouped = subject_wise_students(students)

print("Average Marks per Subject:", avg_per_subject)
print("Topper per Subject:", toppers)
print("Overall Topper:", overall)
print("Students Grouped by Subject:", students_grouped)