How do I check if a list of lists exists in a list of lists?

Question

I got a list of lists b and I want to check if they exist in list a which is also a list of lists.

I'm currently using the following method which is quite time-consuming. Is there a faster way?

b  = [[5], [5, 3], [5, 3, 1], [5, 3, 1, 2]] 
a = [[1, 2, 3], [4, 5, 6], [7, 8, 9]]

result = all(elem in b[0] for elem in a[0])
print(result)
result = all(elem in b[1] for elem in a[0])
print(result)
result = all(elem in b[2] for elem in a[0])
print(result)
result = all(elem in b[3] for elem in a[0])
print(result)

result = all(elem in b[0] for elem in a[1])
print(result)
result = all(elem in b[1] for elem in a[1])
print(result)
result = all(elem in b[2] for elem in a[1])
print(result)
result = all(elem in b[3] for elem in a[1])
print(result) 

result = all(elem in b[0] for elem in a[2])
print(result)
result = all(elem in b[1] for elem in a[2])
print(result)
result = all(elem in b[2] for elem in a[2])
print(result)
result = all(elem in b[3] for elem in a[2])
print(result)

Output:

>>>False
>>>False
>>>False
>>>True
>>>False
>>>False
>>>False
>>>False
>>>False
>>>False
>>>False
>>>False

Is that the output you want? False, False, False, True, False etc.? — khelwood, Mar 03 '21 at 13:35
II don't understand the question. If you want to check if the content of each inner list of `b` is contained in any inner list of `a` then you should have only 4 outputs because there are only 4 inner lists in `b`. — Matthias, Mar 03 '21 at 13:45
Additionally: Your code doesn't check what you described. In your code you check if the content of each inner list of `a` is contained in any inner list of `b`. Please clarify. — Matthias, Mar 03 '21 at 13:53

Allan Wind · Answer 1 · 2021-03-03T13:52:00.730

0

You do the same thing with a double loop O(n^2):

for i in range(len(a)):
    for j in range(len(b)):
        print(all(elem in a[i] for elem in b[j]))

edited Mar 03 '21 at 13:52

answered Mar 03 '21 at 13:39

Allan Wind

23,068
5
28
38

score 0 · Answer 2 · answered Mar 03 '21 at 13:39

0

for i in range(len(b)):
   if b[i] in a:
      return True
   else:
      return False

answered Mar 03 '21 at 13:39

throwaway

55
5

How do I check if a list of lists exists in a list of lists?

2 Answers2

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