Thanks Martin...It works well
Maarten buis wrote:
> --- Maarten buis wrote:
>
>>> bys country (year): gen initgdp = gdp[_n==1]
>>> bys country (year): replace initgdp = sum(initgdp)
>>>
>
> --- Choudry T Shehzad <[email protected]> wrote:
> <snip>
>
>> When I use your command
>>
>> bys country (year): gen initgdp = gdp[_n==1980]
>> bys country (year): replace initgdp = sum(initgdp)
>>
>> all values of initgdp become zeros
>>
>
> _n refers to the observation number and not to the value a variable may
> take. So, the first observation is _n == 1 and not _n == 1980 (which is
> the 1980th observation, which is missing, and -sum()- treats missings
> as zeros, which is why you ended up with all zeros).
>
> -- Maarten
>
>
> -----------------------------------------
> Maarten L. Buis
> Department of Social Research Methodology
> Vrije Universiteit Amsterdam
> Boelelaan 1081
> 1081 HV Amsterdam
> The Netherlands
>
> visiting address:
> Buitenveldertselaan 3 (Metropolitan), room N515
>
> +31 20 5986715
>
> http://home.fsw.vu.nl/m.buis/
> -----------------------------------------
>
>
>
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