使用2d numpy.array索引2d numpy.array

Question

I have an N-by-2 numpy array of 2d coordinates named coords , and another 2d numpy array named plane . What I want to do is like

for x,y in coords:
    plane[x,y] = 0

but without for loop to improve efficiency. How to do this with vectorized code? Which function or method in numpy to use?

Answer 1

You can try plane[coords.T[0], coords.T[1]] = 0 Not sure this is what you want. For example:

Let,

plane = np.random.random((5,5))
coords = np.array([ [2,3], [1,2], [1,3] ])

Then,

plane[coords.T[0], coords.T[1]] = 0

will give:

array([[ 0.41981685,  0.4584495 ,  0.47734686,  0.23959934,  0.82641475],
   [ 0.64888387,  0.44788871,  0.        ,  0.        ,  0.298522  ],
   [ 0.22764842,  0.06700281,  0.04856316,  0.        ,  0.70494825],
   [ 0.18404081,  0.27090759,  0.23387404,  0.02314846,  0.3712009 ],
   [ 0.28215705,  0.12886813,  0.62971   ,  0.9059715 ,  0.74247202]])