NumPy: calculate averages with NaNs removed

Question

How can I calculate matrix mean values along a matrix, but to remove nan values from calculation? (For R people, think na.rm = TRUE).

Here

Answer 1

'''define dataMat'''
numFeat= shape(datMat)[1]
for i in range(numFeat):
     meanVal=mean(dataMat[nonzero(~isnan(datMat[:,i].A))[0],i])