[R] how can I save the estimates of a regression model in a file?

[Chuck Cleland]

On 11/5/2008 12:12 PM, pilar schneider wrote:
> Dear all
> I need some help with R.
> How can I save the estimates of a regression model in a file?
> 
> here is what I did:
> 
> 1) this is my regression model:
> fit1 <- lm(logmilk ~ logdays + days, data=data2)
> 
> 2) however, I want to get the parameters estimates for each individual (by
> group):
> so i did the following:
> by(data2, list(data2$V2),function(.data2) lm(logmilk ~ logdays + days, data=
> .data2))
> 
> 3) Then to keep the estimates in a file I did:
> res1 <- by(data2, list(data2$V2),function(.data2) lm(logmilk ~ logdays + V5,
> data= .data2))
> 
> 4) and this is what I  get for each individual:
> : 1
> Call:
> lm(formula = logmilk ~ logdays + days, data = .data2)
> Coefficients:
> (Intercept)      logdays           days
>    3.414105     0.069387    -0.001732
> 
> ---------------------------------------------------------------------------
> : 2
> Call:
> lm(formula = logmilk ~ logdays + days, data = .data2)
> 
> Coefficients:
> (Intercept)      logdays           days
>   3.2276114    0.1223412   -0.0006836
> 
> and so on:
> 
> 
> 5) THE QUESTION is:
> 
> there is a way in R to get an output file as you get in SAS when you use:
> prog reg data=xxx outest=estimate;
> I would need an output that looks like this:
> 
> individual     intercept     logdays   days           etc
> 1           3.414105        0.069387   -0.0006836
> 2           3.2276114       0.1223412  -0.0006836
> 
> n           ........               ..........       .........
> THANKS FOR YOUR HELP
> 
> Maria 

  Consider something like this:

as.data.frame(t(sapply(split(data2, data2$V2),
function(x){coef(lm(logmilk ~ logdays + days, data = x))})))

-- 
Chuck Cleland, Ph.D.
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