a=np.array([[[1,1],[2,2],[3,3]],[[4,4],[5,5],[6,6]],[[7,7],[8,8],[9,9]],[[10,10],[11,11],[12,12]]]) print a print a.shape b=a.mean(0).shape c=a.mean(1).shape d=a.mean(2).shape print b print c print d output: [[[ 1 1] [ 2 2] [ 3 3]] [[ 4 4] [ 5 5] [ 6