Check if each element of a tensor is contained in a list

user_9067615 0
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Say I have a tensor A and a container of values vals. Is there a clean way of returning a Boolean tensor of the same shape as A with each element being whether that element of A is contained within vals? e.g:

A = torch.tensor([[1,2,3],
                  [4,5,6]])
vals = [1,5]

# Desired output
torch.tensor([[True,False,False],
              [False,True,False]])
pytorch python comparison
3 Answers

You can achieve this with a for loop:

sum(A==i for i in B).bool()
user_90676150

You can simply do like this:

result = A.apply_(lambda x: x in vals).bool()

Then result will contain this tensor:

tensor([[ True, False, False],
        [False,  True, False]])

Here I simply used a lambda function and the apply_ method that you can find in the official documentation.

user_120992400 
[list(map(lambda x: x in vals, thelist)) for thelist in A]
user_9422060
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