numpy.median — NumPy v1.13 Manual (original) (raw)

Compute the median along the specified axis.

Returns the median of the array elements.

Given a vector V of length N, the median of V is the middle value of a sorted copy of V, V_sorted - i e., V_sorted[(N-1)/2], when N is odd, and the average of the two middle values of V_sorted when N is even.

a = np.array([[10, 7, 4], [3, 2, 1]]) a array([[10, 7, 4], [ 3, 2, 1]]) np.median(a) 3.5 np.median(a, axis=0) array([ 6.5, 4.5, 2.5]) np.median(a, axis=1) array([ 7., 2.]) m = np.median(a, axis=0) out = np.zeros_like(m) np.median(a, axis=0, out=m) array([ 6.5, 4.5, 2.5]) m array([ 6.5, 4.5, 2.5]) b = a.copy() np.median(b, axis=1, overwrite_input=True) array([ 7., 2.]) assert not np.all(a==b) b = a.copy() np.median(b, axis=None, overwrite_input=True) 3.5 assert not np.all(a==b)