How to bin a 2D array in numpy?

Question

I\'m new to numpy and I have a 2D array of objects that I need to bin into a smaller matrix and then get a count of the number of objects in each bin to make a heatmap. I fo

Answer 1

You can reshape the array to a four dimensional array that reflects the desired block structure, and then sum along both axes within each block. Example:

>>> a = np.arange(24).reshape(4, 6)
>>> a
array([[ 0,  1,  2,  3,  4,  5],
       [ 6,  7,  8,  9, 10, 11],
       [12, 13, 14, 15, 16, 17],
       [18, 19, 20, 21, 22, 23]])
>>> a.reshape(2, 2, 2, 3).sum(3).sum(1)
array([[ 24,  42],
       [ 96, 114]])

If a has the shape m, n, the reshape should have the form

a.reshape(m_bins, m // m_bins, n_bins, n // n_bins)