How can you turn an index array into a mask array in Numpy?

Question

Is it possible to convert an array of indices to an array of ones and zeros, given the range? i.e. [2,3] -> [0, 0, 1, 1, 0], in range of 5

I\'m trying to automate so

Answer 1

For a single dimension, try:

n = (15,)
index_array = [2, 5, 7]
mask_array = numpy.zeros(n)
mask_array[index_array] = 1

For more than one dimension, convert your n-dimensional indices into one-dimensional ones, then use ravel:

n = (15, 15)
index_array = [[1, 4, 6], [10, 11, 2]] # you may need to transpose your indices!
mask_array = numpy.zeros(n)
flat_index_array = np.ravel_multi_index(
    index_array,
    mask_array.shape)
numpy.ravel(mask_array)[flat_index_array] = 1