如何用Python的add_course函数替换列表中低成绩课程元组

def add_student(students, name):
    if name not in students:
        students[name] = []

def print_student(students, name):
    if name not in students:
        print(f"{name}: no such person in the database")
    elif len(students[name]) < 1:
        print(f"{name}:")
        print(" no completed courses")
    else:
        print(f"{name}:")
        print(f" {len(students[name])} completed courses:")
        for course in students[name]:
            print(f"  {course[0]} {course[1]}")
        av_grade = sum(course[1] for course in students[name]) / len(students[name])
        print(f" average grade {av_grade}")

def add_course(students, name, course: tuple):
    course_name, new_score = course
    # 成绩为0时直接返回，不添加课程
    if new_score == 0:
        return
    
    # 遍历已修课程，查找同名课程
    for idx, (existing_course, existing_score) in enumerate(students[name]):
        if existing_course == course_name:
            # 新成绩更高则替换原有课程记录
            if new_score > existing_score:
                students[name][idx] = course
            # 无论是否替换，都终止函数，避免重复添加
            return
    
    # 未找到同名课程，添加新课程
    students[name].append(course)

if __name__ == "__main__":
    students = {}
    add_student(students, "Peter")
    add_course(students, "Peter", ("Introduction to Programming", 3))
    add_course(students, "Peter", ("Advanced Course in Programming", 2))
    add_course(students, "Peter", ("Data Structures and Algorithms", 0))
    add_course(students, "Peter", ("Introduction to Programming", 2))
    print_student(students, "Peter")

• 修复课程存在性判断逻辑：原代码用course[0] in students[name]判断课程是否存在，这是错误的——students[name]存储的是课程元组，而course[0]是字符串，永远无法匹配。现在改为遍历列表中的元组，检查元组的第一个元素（课程名）是否匹配。
• 实现成绩替换逻辑：找到同名课程后，对比新旧成绩，只有新成绩更高时，才用新的课程元组替换原有记录；若新成绩更低或相等，直接返回不做操作。
• 简化平均成绩计算：原代码用两次循环计算平均分，改为用生成器表达式结合sum()函数，更简洁高效。
• 优化print_student分支：将elif len(students[name]) > 0改为else，逻辑更简洁，因为前面已经判断过学生存在且课程列表为空的情况。

运行修正后的代码，输出将符合预期：

Peter:
 2 completed courses:
  Introduction to Programming 3
  Advanced Course in Programming 2
 average grade 2.5

内容的提问来源于stack exchange，提问作者John Fox