如何比較兩個集合，其中的每個元素是列表？

Question

這是我的代碼。

a = [ 
     ['StarList', 'StarId38', 'ShipList'] 
    ] 
b = [ 
     ['StarList', 'StarId3', 'ShipList'], 
     ['StarList', 'StarId4', 'ShipList'] 
    ] 
assert set(a) == set(b) # False 

a = [ 
     ['StarList', 'StarId4', 'ShipList'], 
     ['StarList', 'StarId3', 'ShipList'] 
    ] 
assert set(a) == set(b) # True 

它不工作：

Traceback (most recent call last): 
    File "compare.py", line 8, in <module> 
     assert set(a) == set(b) # False 
TypeError: unhashable type: 'list' 

好了，該怎麼辦呢？

Answer 1

轉換內部列表來元組或比較之前的一些其他類型的哈希的。

In [52]: a = [        
     ['StarList', 'StarId38', 'ShipList'] 
    ] 

In [53]: b = [        
     ['StarList', 'StarId3', 'ShipList'], 
     ['StarList', 'StarId4', 'ShipList'] 
    ] 

In [54]: set(map(tuple, a)) == set(map(tuple, b)) 
Out[54]: False 

In [55]: a = [ 
    ....:   ['StarList', 'StarId4', 'ShipList'], 
    ....:   ['StarList', 'StarId3', 'ShipList'] 
    ....:  ] 

In [56]: set(map(tuple,a))==set(map(tuple,b)) 
Out[56]: True 

Answer 2

set()在列表元素不可用時不起作用（例如列表）。所以首先你應該考慮如果你真的必須使用set。除去在這種情況下重複的另一種方法是itertools.groupby：

import itertools 
unique_a = [k for k,_ in itertools.groupby(a)] 
unique_b = [k for k,_ in itertools.groupby(b)] 
unique_a.sort() 
unique_b.sort() 

並嘗試（你的第二個案例）：

>>> unique_a == unique_b 
True