Creating a tumbling windows in python

Question

Just wondering if there is a way to construct a tumbling window in python. So for example if I have list/ndarray , listA = [3,2,5,9,4,6,3,8,7,9]. Then how could I f

Answer 1

Using numpy, you can extend the list with zeroes so its length is divisible by the window size, and reshape and compute the maxalong the second axis:

def moving_maxima(a, w):
    mod = len(a)%w
    d = w if mod else mod
    x = np.r_[a, [0]*(d-mod)]
    return x.reshape(-1,w).max(1)

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Some examples:

moving_maxima(listA,2)
# array([3., 9., 6., 8., 9.])

moving_maxima(listA,3)
#array([5, 9, 8, 9])

moving_maxima(listA,4)
#array([9, 8, 9])