[email protected]
>
> I was wondering if anyone can help me on this programming
> problem. I have
> an array of variables, let's say x1-x20, and I wish to
> refer to one of them
> using values in another variable (let's call it m), in an
> equation so that
> I can use one equation that is different for each
> observation. In other
> words, if my equation is y = x`m' + 1 and m = 2, then the
> equation for that
> particular observation would be y = x2 + 1. Here is a
> partial list of what
> I'm talking about:
>
> obs m equation
>
> 1 2 y = x2 + 1
> 2 3 y = x3 + 1
> 3 6 y = x6 + 1
> 4 8 y = x8 + 1
>
> I don't think using a global or macro variable works
> because those only
> take on one value and because the equation is essentially
> the model in a
> non-linear estimation, I don't think I could use a loop. I
> was wondering
> if there are more options out there. Thank you!
Something like this may be what you want.
qui gen y = .
local n = _N
qui forval i = 1 / `n' {
local m = m[`i']
replace y = x`m' + 1 in `i'
}
In Stata 8, this can be shortened a little:
qui gen y = .
qui forval i = 1 / `=_N' {
local m = m[`i']
replace y = x`m' + 1 in `i'
}
Nick
[email protected]
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