Hello Svend,
I have a question. Where did you read that the command
if j==1
will be testing the FIRST observation. I don't think that it is in the
stata help for if. Could you point me in the right direction here.
Also I liked your use of the local in that way. I did not think of
that . Did you read that somewhere too ?
Thank you,
Ashim.
On Thu, Nov 13, 2008 at 2:10 PM, Svend Juul <[email protected]> wrote:
>
> Ashim wrote:
>
> I realize that there are 2 kinds if's in Stata.
>
> Type 1 : would be something like replace j = 2 if k==2
> here the replace in j would happen ONLY in the corresponding
> observation of k. THIS IS WHAT I WANT.
>
>
> Type 2 : the programming if something like
>
> local j
>
> if `j'==2 {
>
> do something.
>
> }
>
> **************************************************************
>
> I guess I want to do something which is in between the above 2.
>
> I want to say the following : --
>
> replace j=2 if k==2
> replace m=2 if k==2
> replace n=2 if k==2
>
> in ONE shot.
>
> so I try : -
> ************************************** Block A
> if k==2 {
> replace j=2
> replace m=2
> replace n=2
> }
> *********************************************
> This does not work. Because k==2 would mean k==2 in ALL observations.
> ...
>
> ===============================================================
>
> Actually the command -if k==2- means k==2 in the FIRST observation.
> In Stata terms, your type 1 -if- is a qualifier; your type 2 -if- is
> a command.
>
> There is probably no smart way to do what you want. In some cases
> you might benefit from putting the condition in a macro, like:
>
> sysuse auto.dta , clear
> local X "if foreign==1"
> replace price = 1 `X'
> replace weight = 2 `X'
>
> Hope this helps
> Svend
> __________________________________________
>
> Svend Juul
> Institut for Folkesundhed, Afdeling for Epidemiologi
> (Institute of Public Health, Department of Epidemiology)
> Vennelyst Boulevard 6
> DK-8000 Aarhus C, Denmark
> Phone: +45 8942 6090
> Home: +45 8693 7796
> Email: [email protected]
> __________________________________________
>
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