[Python] Cumsum reset at NaN

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
...
15 1
10 NaN
11 1
12 1
13 1
9 NaN
8 NaN
7 NaN
6 NaN
3 NaN
4 1
5 1
2 NaN
1 NaN
0 NaN


I would like to calculate cumsum of this serie but it should be reset (set to zero) at the location of the NaNs like below:

3382 0
3381 0
...
3369 0
3368 0
...
15 1
10 0
11 1
12 2
13 3
9 0
8 0
7 0
6 0
3 0
4 1
5 2
2 0
1 0
0 0


Ideally I would like to have a vectorized solution !

I ever see a similar question with Matlab : Matlab cumsum reset at NaN?

but I don't know how to translate this line d = diff([0 c(n)]);

Continue reading...