Hi, I want to get the mean over an array with 3 dimensions. The array has, say, dimensions 2x3x4 and I want the result to be 3x4; so the averaging is to be done over the 1st dimension. Also, there are some fill values, and I want these to be excluded from the calculation. I know I can use the ma module to locate the fill values, but after that I am unsure how to exclude them, and how to do the averaging. In [150]: x = rand(2,3,4) In [151]: x[0,2,1]=999 # fill value In [152]: x[1,2,3]=999 In [153]: x[0,1,3]=999 In [154]: x Out[154]: array([[[ 3.01880915e-02, 5.77085271e-02, 7.59176038e-01, 4.15271486e-01], [ 5.48643693e-01, 3.84995126e-01 , 5.01683678e-01, 9.99000000e+02], [ 5.72779004e-01, 9.99000000e+02, 4.18143934e-01, 5.84781674e-01]], [[ 8.90443158e-01, 3.76986788e-01, 8.81270409e-01, 5.19094405e-01], [ 8.12944573e-01, 3.89858156e-01, 5.99219891e-01, 9.99000000e+02], [ 2.31215256e-01, 5.93222883e-01, 2.45004093e-01, 9.18647954e-01]]]) In [155]: Thanks in advance for any help. -Evan