python - 如何将嵌套字典变成矩阵列表？

Question

我有以下字典:

dictionary = {'test1.txt': {'apple': 1, 'banana': 1, 'lemon': 1},
'test2.txt': {'apple': 1, 'banana': 1},
'test3.txt': {'apple': 1, 'lemon': 2},
'test4.txt': {'apple': 1, 'lemon': 1, 'grape': 1}}

应该变成:

[['', 'test1.txt', 'test2.txt', 'test3.txt', 'test4.txt'],
['lemon', 1, 0, 2, 1],
['apple', 1, 1, 1, 1],
['banana', 1, 1, 0, 0],
['grape', 0, 0, 0, 1]]

我已经尝试了下面的代码，但我总是遇到错误:

keycount = []                                                                      
for i, f in enumerate(dictionary):                                                 
    for t in f:                                                                      
        if t not in keycount:                                                      
             keycount[t] = [0]*len(dictionary)                                         
        vocabulary[t][i]+=1 

有没有人知道如何解决这个问题？ 请不要使用外部库，我只是在练习:)

Answer 1

没有外部库

dictionary = {'test1.txt': {'apple': 1, 'banana': 1, 'lemon': 1},
'test2.txt': {'apple': 1, 'banana': 1},
'test3.txt': {'apple': 1, 'lemon': 2},
'test4.txt': {'apple': 1, 'lemon': 1, 'grape': 1}}

# all the keys used by all dictionaries
#all_keys = set().union(*(d.keys() for d in dictionary.values()))
# update using @JonClements suggestion
all_keys = set().union(*dictionary.values())

# Start with list of keys
lst = [list(dictionary.keys())]

# Add item count from each dictionary
lst += [[k] + [d.get(k, 0) for d in dictionary.values()] for k in all_keys]
print(lst)

输出

[['test1.txt', 'test2.txt', 'test3.txt', 'test4.txt'], 
 ['banana', 1, 1, 0, 0], 
 ['apple', 1, 1, 1, 1], 
 ['lemon', 1, 0, 2, 1], 
 ['grape', 0, 0, 0, 1]]