13.4) Useful Functions
You’ll often want to calculate the sum, minimum or maximum of an array:
>>> a = np.arange(15).reshape(3,5) >>> a array([[ 0, 1, 2, 3, 4], [ 5, 6, 7, 8, 9], [10, 11, 12, 13, 14]]) >>> a.sum() 105 >>> a.min() >>> a.max() 14
You can also apply these functions to specific dimensions (axis) of an array:
>>> a.min(axis=0) # min along first axis eg vertical Array([ 0, 1, 2, 3, 4]) >>> a.cumsum(axis=1) # cumulative sum along the 2nd axis (horizontal) array([[ 0, 1, 3, 6, 10], [ 5, 11, 18, 26, 35], [10, 21, 33, 46, 60]])