It seems you have a list of tensors. For each tensor you can see its size(). If you want, you can convert a tensor to numpy array using numpy():
Returns a list of tensor shapes:
>> [t.size() for t in my_list_of_tensors]
Returns a list of numpy arrays:
>> [t.numpy() for t in my_list_of_tensors]
In terms of performance, it is always best to avoid casting of tensors into numpy arrays, If you only need to check the shape of a tensor, use size() function.