TypeError：string indices必须是整数，而不是str //使用dict [英] TypeError: string indices must be integers, not str // working with dict

问题描述

我正在尝试定义一个程序，涉及（课程，人），它将输入课程结构和一个人，并返回一个描述所有课程的词典

I am trying to define a procedure, involved(courses, person), that takes as input a courses structure and a person and returns a Dictionary that describes all the courses the person is involved in.

这是我的涉及（课程，人） function：

Here is my involved(courses, person) function:

def involved(courses, person):
    for time1 in courses:
        for course in courses[time1]:
            for info in time1[course]:
                print info

这是我的字典：

courses = {
    'feb2012': { 'cs101': {'name': 'Building a Search Engine',
                           'teacher': 'Dave',
                           'assistant': 'Peter C.'},
                 'cs373': {'name': 'Programming a Robotic Car',
                           'teacher': 'Sebastian',
                           'assistant': 'Andy'}},
    'apr2012': { 'cs101': {'name': 'Building a Search Engine',
                           'teacher': 'Dave',
                           'assistant': 'Sarah'},
                 'cs212': {'name': 'The Design of Computer Programs',
                           'teacher': 'Peter N.',
                           'assistant': 'Andy',
                           'prereq': 'cs101'},
                 'cs253': 
                {'name': 'Web Application Engineering - Building a Blog',
                           'teacher': 'Steve',
                           'prereq': 'cs101'},
                 'cs262': 
                {'name': 'Programming Languages - Building a Web Browser',
                           'teacher': 'Wes',
                           'assistant': 'Peter C.',
                           'prereq': 'cs101'},
                 'cs373': {'name': 'Programming a Robotic Car',
                           'teacher': 'Sebastian'},
                 'cs387': {'name': 'Applied Cryptography',
                           'teacher': 'Dave'}},
    'jan2044': { 'cs001': {'name': 'Building a Quantum Holodeck',
                           'teacher': 'Dorina'},
               'cs003': {'name': 'Programming a Robotic Robotics Teacher',
                           'teacher': 'Jasper'},
                     }
    }

当我试图测试我的代码时：

When I'm trying to test my code:

>>>print involved(courses, 'Dave')

Python给我一个错误：

Python give me an error:

for info in time1[course]:
TypeError: string indices must be integers, not str

如何解决？

谢谢。

推荐答案

time1 是最外层字典的关键字，例如 feb2012 。那么你试图索引字符串，但你只能用整数来做。我想你想要的是：

time1 is the key of the most outer dictionary, eg, feb2012. So then you're trying to index the string, but you can only do this with integers. I think what you wanted was:

for info in courses[time1][course]:

当你要经历每个字典，你必须添加另一个嵌套。

As you're going through each dictionary, you must add another nest.

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