# [PYTHON MATRIX-SIG] handling missing data values in NumPy

**Jim Hugunin
**
hugunin@mit.edu

*Mon, 2 Jun 1997 13:18:35 -0400*

>* I often deal with time sequences of 2D arrays that have
*>* some values missing at random times. I want to obtain
*>* an average of these sequences along the time axis
*>* taking into account the missing values.
*
I can tell you how I solve the problem in my own code. No guarantees that this is
appropriate for you though...
>>>* from Numeric import *
*>>>* data = array([1,2,666,4,5])
*>>>* valid = array([1,1, 0,1,1])
*>>>* print sum(data*valid)/sum(valid)
*3
If you do a lot of this sort of thing, you could encapsulate this way of
representing arrays with missing values into a new python object, but that's
possibly overkill.
-Jim
_______________
MATRIX-SIG - SIG on Matrix Math for Python
send messages to: matrix-sig@python.org
administrivia to: matrix-sig-request@python.org
_______________