用列表值反转字典 [英] Inverting a dictionary with list values

问题描述

所以，我将此索引作为字典.

So, I have this index as a dict.

index = {'Testfil2.txt': ['nisse', 'hue', 'abe', 'pind'], 'Testfil1.txt': ['hue', 'abe', 
'tosse', 'svend']}

我需要反转索引，这样它才能成为字典，将重复的值合并为一个键，并以2个原始键作为值，如下所示:

I need to invert the index so it will be a dict with duplicates of values merged into one key with the 2 original keys as values, like this:

inverse = {'nisse' : ['Testfil2.txt'], 'hue' : ['Testfil2.txt', 'Testfil1.txt'], 
'abe' : ['Testfil2.txt', 'Testfil1.txt'], 'pind' : ['Testfil2.txt'], 'tosse' : 
['Testfil1.txt'], 'svend' : ['Testfil1.txt']

是的，我手动输入了以上内容.

Yes, I typed the above by hand.

我的教科书具有反转字典的功能:

My textbook has this function for inverting dictionaries:

def invert_dict(d): 
    inverse = dict() 
    for key in d: 
        val = d[key] 
        if val not in inverse: 
            inverse[val] = [key] 
        else: 
            inverse[val].append(key) 
return inverse

它对于简单的键:值对工作正常

It works fine for simple key:value pairs

但是，当我尝试使用包含诸如index之类的值的列表的dict时，我得到以下错误消息:

BUT, when I try that function with a dict that has lists as values such as my index I get this error message:

invert_dict(index)

Traceback (most recent call last):
    File "<pyshell#153>", line 1, in <module>
invert_dict(index)
    File "<pyshell#150>", line 5, in invert_dict
if val not in inverse:
TypeError: unhashable type: 'list'

我已经花了一个小时寻找解决方案，这本书没有帮助，我怀疑我可以以某种方式使用元组，但是我不确定如何使用.有帮助吗?

I have searched for an hour looking for a solution, the book is no help, and I suspect that I can use tuples in some way, but I am not sure how. Any help?

推荐答案

我已经尝试过，并且您想使用val not in inverse，但是无法检查列表是否在字典中". (val是列表)

I've tried around and you want to use val not in inverse but it can't be checked if a "list is in a dict". (val is a list)

对您的代码进行简单的更改即可完成您想要的操作:

For your code a simple change will do what you want:

def invert_dict(d): 
    inverse = dict() 
    for key in d: 
        # Go through the list that is saved in the dict:
        for item in d[key]:
            # Check if in the inverted dict the key exists
            if item not in inverse: 
                # If not create a new list
                inverse[item] = [key] 
            else: 
                inverse[item].append(key) 
    return inverse

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