python - TypeError : string indices must be integers, not str，它指的是哪一部分？

Question

我是 python 的初学者，可能会在这里提出一些基本问题。有人可以帮忙吗？

我想得到每个学生的平均值，然后计算这些平均值的平均值。获取“TypeError:字符串索引必须是整数，而不是 str”。无法弄清楚它指的是什么以及如何修改。这是我的代码:

lloyd = {
    "name": "Lloyd",
    "homework": [90.0, 97.0, 75.0, 92.0],
    "quizzes": [88.0, 40.0, 94.0],
    "tests": [75.0, 90.0]
}
alice = {
    "name": "Alice",
    "homework": [100.0, 92.0, 98.0, 100.0],
    "quizzes": [82.0, 83.0, 91.0],
    "tests": [89.0, 97.0]
}
tyler = {
    "name": "Tyler",
    "homework": [0.0, 87.0, 75.0, 22.0],
    "quizzes": [0.0, 75.0, 78.0],
    "tests": [100.0, 100.0]
}


def average(numbers):
    total = sum(numbers)
    total = float(total)
    return total/len(numbers)


def get_average(student):
    homework = average(student["homework"])
    quizzes = average(student["quizzes"])
    tests = average(student["tests"])
    return 0.1*homework + 0.3*quizzes + 0.6*tests


def get_class_average(students):
    results = []
    for student in students:
        result = get_average(student)
        results.append(result)
    return average(results)

students = ["lloyd", "alice", "tyler"]
print get_class_average(students)

Answer 1

当你用引号括起一个名字时，它是一个字符串文字，而不是一个变量。

>>> x = 3
>>> x
3
>>> 'x'
'x'

使用 students = [lloyd, alice, tyler] 来引用您在上面定义的变量。