Cumsum reset at NaN

Question

If I have a pandas.core.series.Series named ts of either 1\'s or NaN\'s like this:

3382   NaN
3381   NaN
...
3369   NaN
3368   NaN
         


        

Answer 1

A simple Numpy translation of your Matlab code is this:

import numpy as np

v = np.array([1., 1., 1., np.nan, 1., 1., 1., 1., np.nan, 1.])
n = np.isnan(v)
a = ~n
c = np.cumsum(a)
d = np.diff(np.concatenate(([0.], c[n])))
v[n] = -d
np.cumsum(v)

Executing this code returns the result array([ 1., 2., 3., 0., 1., 2., 3., 4., 0., 1.]). This solution will only be as valid as the original one, but maybe it will help you come up with something better if it isn't sufficient for your purposes.