Why doesn't cmap argument work in mathplotlib?

Question

Python

Hello. Faced such a problem.
There is a task "The code in the next cell loads a photo of a kitten as a Numpy array."
I wrote the code and it seems to work correctly, but the image does not turn gray as in this photo
. I get something like this

Please help)

def slicing(kitten):
    
    img1 = [[[y[0], 0, 0] for y in x] for x in kitten]
    img2 = [[[0, y[0], 0] for y in x] for x in kitten]
    img3 = [[[0, 0, y[0]] for y in x] for x in kitten]
    
    fig, (img1_, img2_, img3_) = plt.subplots(
        nrows=3, ncols=1,
        figsize = (9,12),
        sharex=True)
    
    
    img1_.set_title("R")
    img1_.imshow(img1, cmap = 'gray')
    
    img2_.set_title("G")
    img2_.imshow(img2, cmap = 'gray')
    
    img3_.set_title("B")
    img3_.imshow(img3, cmap = 'gray')
    
    plt.show()
    
        
slicing(kitten)

Answer 1

Because slice it wrong, IMHO. It is necessary not to leave only one color component, but to replace two other components with it: [RGB] -> [RRR], [GGG], [BBB], and not [R00], [0G0], [00B].
Well, try something like this: https://stackoverflow.com/questions/25625952/matpl...