Generate a 2D boolean array from tuples

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说谎
说谎 2020-12-11 23:41

How can I generate a 2D boolean array using a list of tuples that shows the indices of the True values?

For example I have the following list of tuples:



        
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  •  一个人的身影
    2020-12-12 00:06

    zip(*...) is a handy way of 'transposing' a list of lists (or tuples). And A[x,y] is the same as A[(x,y)].

    In [397]: lst = [(0,1), (0, 2), (1, 0), (1, 3), (2,1)]
    
    In [398]: tuple(zip(*lst))    # make a tuple of tuples (or lists)
    Out[398]: ((0, 0, 1, 1, 2), (1, 2, 0, 3, 1))
    
    In [399]: A=np.zeros((3,4),dtype=bool)  # make an array of False
    
    In [400]: A[tuple(zip(*lst))] = True  # assign True to the 5 values
    
    In [401]: A
    Out[401]: 
    array([[False,  True,  True, False],
           [ True, False, False,  True],
           [False,  True, False, False]], dtype=bool)
    

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