a.py

students_data = [
	["Alice", [85, 90, 92], ["Math", "English", "Science"]],
	["Bob", [78, 88, 80], ["Math", "English", "Science"]],
	["Charlie", [92, 94, 89], ["Math", "English", "Science"]],
	["David", [80, 85, 88], ["Math", "English", "Science"]],
]

def getStudents(arr: list):

	# Traversal
	for i in arr:
		ave = 0
		for j in i[1]:
			ave += j
		ave /= len(i[1])
		ave *= 100
		ave //= 1
		ave /= 100
		if(len(i) < 4):
			i.append(ave)

	# Sort
	for i in range(len(arr)):
		for j in range(len(arr)):
			if arr[i][-1] < arr[j][-1]:
				arr[i], arr[j] = arr[j], arr[i]

	return arr

students_data = getStudents(students_data)
print(f"Sorted by Average: {students_data}")

print()

students_data.append(["Eva", [95, 91, 88], ["Math", "English", "Science"]])
print(f"Added Eva: {students_data}")

print()

students_data = getStudents(students_data)
print(f"New sort with Eva: {students_data}")
print()

students_data.pop(0)
print(f"Remove lowest average: {students_data}")

print()

english_scores = []
for i in range(len(students_data)):
	english_scores.append(students_data[i][1][1])
print(f"All English grades: {students_data}")

print()

maths = [i for i in students_data]
for i in range(len(maths)):
	for j in range(len(maths)):
		if maths[i][1][0] > maths[j][1][0]:
			maths[i], maths[j] = maths[j], maths[i]

print(f"Sorted by Math: {maths}")