Tak Wai,
The loop below copies all non-missing observations from variables v1
to v10 to variables w1 to w10. The macro s counts the number of
non-missing observations in variables v1 to v10.
local s = 0
forvalues i = 1/10 {
replace w`i' = v`i' if v`i'<.
count if v`i'<.
local s = `s' + r(N)
di `s'
}
The statement "s=1" is not valid Stata, you probably mean "generate
s=1". The command "local s1=s" assigns the first observation in
variable s to the local s1. The command "replace s=s+1 if v`i'<."
adds 1 to all observations in variable s if the first observation in
variable v`i' is missing.
The command "replace w`s1'=v`i' if v`i'<." indicates that you may be
thinking in terms of a loop over observations, not variables. Such a
loop is neither efficient nor necessary but if you want it you need
different code from the one above.
Friedrich
--- Tak-wai Chau <[email protected]> wrote:
> Hi,
>
> I would like to ask something about using macro in loops. I have
> tried to find it in the archive and FAQ for some time but I don't
> get it.
>
> Sorry if I have overlooked some obvious things.
>
> I would like to update certain variables according to the value
> taking by a particular variable, and this value differs by
> observations. Then what I should do?
>
> For example, if I want to transfer value of non-missing variables
> from V1-V10 to W1-W10. But I don't want to variables carrying
> missing value between. I use s to count the number of non-missing
> values I have covered at that point.
>
> The following is what I think of but doesn't work.
>
> s=1
> forvalues i=1/10 {
> local s1=s
> replace w`s1'=v`i' if v`i'<.
> replace s=s+1 if v`i'<.
> }
>
> I know the problem is at the local statement.
>
> What should I do?
>
> Thank you very much!
>
> Tak Wai Chau
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