题解 | #牛牛的绩点#

grade = [
    ['A', 4],
    ['B', 3],
    ['C', 2],
    ['D', 1],
    ['F', 0],
]

input_grade = []

current_class = input() # 'A'
while current_class != 'False':
    current_grade = int(input())    # 3
    input_grade.append([current_class, current_grade])#将输入的登记和分数存入
    current_class = input()#更新

# print(input_grade)

all_grade = 0
all_xuefen = 0

for item in input_grade:    # ['A', 3]
    for item2 in grade:
        if item[0] == item2[0]:#找到对应等级
            all_grade += item[1] * item2[1]#算出绩点*学费
            all_xuefen += item[1]#总学分

print("{:.2f}".format(all_grade / all_xuefen))

常用循环
i = 0
while i < len(input_grade):
     item = input_grade[i]
    i += 1#更新