Re: st: Duration data- count number of spells with ref to current spell

[Nick Cox <njcoxstata@gmail.com>]

clear
input person eventStart str20 eventType
1                  10                  work
1                  14                  lunch
1                  15                  work
1                  16                  work
1                  33                  shopping
1                  34                  shopping
2                  12                  sleep
2                  15                  work
2                  20                  gaming
end
bysort person (eventStart) : gen cumact = sum(eventType == "work")
by person  : gen before = cond(_n == 1, 0, cumact[_n-1])
by person  : gen after = cumact[_N] - cumact

Nick
njcoxstata@gmail.com


On 26 August 2013 22:01, Sriram Narayanamoorthy <nsriram@utexas.edu> wrote:
> Hi Nick,
>
> Thanks for the response. Though, I am not quite sure I understand the
> solution. Is the variable "activity" in your toy dataset is the
> eventType I referred to in my question or is it something else. I
> think your approach would give me the net time spend in other
> activities before current activity (or time remaining to spend). What
> I want to do is count the number of activity of a particular type.
>
> I have provided an example below:
>
> person          eventStart       eventType
> 1                  10                  work
> 1                  14                  lunch
> 1                  15                  work
> 1                  16                  work
> 1                  33                  shopping
> 1                  34                  shopping
>
>
> The dataset is sorted in person and eventStart. Say, I want to count
> the number of "work" events before and after the current event - based
> on the eventStart variable. This would be my output. For, example for
> the lunch tour, I have 1 work tours before time period 14 and 2 work
> tours after time period 14.
>
> person   eventStart             eventType           numWorkBefore
>          numWorkAfter
> 1                  10                  work                  0
>                            2
> 1                  14                  lunch                 1
>                            2
> 1                  15                  work                  1
>                            1
> 1                  16                  work                  2
>                            0
> 1                  33                  shopping            3
>                          0
> 1                  34                  shopping            3
>                          0
>
> Please let me know if I am misunderstanding your solution.
>
> Thanks,
> -Sriram
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