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

Compute the median along the specified axis, while ignoring NaNs.

Returns the median of the array elements.

New in version 1.9.0.

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([[10.0, 7, 4], [3, 2, 1]]) a[0, 1] = np.nan a array([[ 10., nan, 4.], [ 3., 2., 1.]]) np.median(a) nan np.nanmedian(a) 3.0 np.nanmedian(a, axis=0) array([ 6.5, 2., 2.5]) np.median(a, axis=1) array([ 7., 2.]) b = a.copy() np.nanmedian(b, axis=1, overwrite_input=True) array([ 7., 2.]) assert not np.all(a==b) b = a.copy() np.nanmedian(b, axis=None, overwrite_input=True) 3.0 assert not np.all(a==b)