st: generating sums

[baum <baum@bc.edu>]

Rich asked

> I have a data that looks like this:
>
> _obs_  _x_ _y_
>  1      1   0
>  2      1   0
>  3      0   1
>  4      0   1
>  5      1   0
>  6      0   1
>  7      0   1
>
> I want to generate a 'streak' variable that will make the data look like
> this:
>
> _obs_  _x_ _y_ _z_ _z2_
>  1      1   0   1   0
>  2      1   0   2   0
>  3      0   1   0   1
>  4      0   1   0   2
>  5      1   0   1   0
>  6      0   1   0   1
>  7      0   1   0   2

The recently described tsspell will do just that, since its 'seq' counts 
the length of a spell, i.e. a winning streak:

list
g t=_n
tsset t
tsspell, c(x>0) seq(z)
drop _*
tsspell, c(y>0) seq(z2)
drop _*
list



ssc install tsspell

Kit

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