How to use numpy with 'None' value in Python? How to use numpy with 'None' value in Python? python python

How to use numpy with 'None' value in Python?


You are looking for masked arrays. Here's an example.

import numpy.ma as maa = ma.array([1, 2, None], mask = [0, 0, 1])print "average =", ma.average(a)

From the numpy docs linked above, "The numpy.ma module provides a nearly work-alike replacement for numpy that supports data arrays with masks."


haven't used numpy, but in standard python you can filter out None using list comprehensions or the filter function

>>> [i for i in [1, 2, None] if i != None][1, 2]>>> filter(lambda x: x != None, [1, 2, None])[1, 2]

and then average the result to ignore the None


You can use scipy for that:

import scipy.stats.stats as stm=st.nanmean(vec)