I have a numpy array. I want to create a new array which is the average over every consecutive triplet of elements. So the new array will be a third of the size as the original.
As an example:
np.array([1,2,3,1,2,3,1,2,3])
should return the array:
np.array([2,2,2])
Can anyone suggest an efficient way of doing this? I’m drawing blanks.
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Answer
If your array arr has a length divisible by 3:
np.mean(arr.reshape(-1, 3), axis=1)
Reshaping to a higher dimensional array and then performing some form of reduce operation on one of the additional dimensions is a staple of numpy programming.