On 23 October 2012 13:11, Cera, Tim <t...@cerazone.net> wrote: > I have an array that is peppered throughout in random spots with 'nan'. I > would like to use 'cumsum', but I want it to reset the accumulation to 0 > whenever a 'nan' is encountered. Is there a way to do this? Aside from a > loop - which is what I am going to setup here in a moment.
How about this hackish solution, for a quick non-looping fix? In [39]: a = np.array([1,2,3,4,np.nan,1,2,3,np.nan,3]) idx = np.flatnonzero(np.isnan(a)) a_ = a.copy() a_[idx] = 0 np.add.reduceat(a_, np.hstack((0,idx))) Out[39]: array([ 10., 6., 3.]) Note that if the last element of a is nan, you get a final 0 in the result. Angus -- AJC McMorland Post-doctoral research fellow Neurobiology, University of Pittsburgh _______________________________________________ NumPy-Discussion mailing list NumPy-Discussion@scipy.org http://mail.scipy.org/mailman/listinfo/numpy-discussion
