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

2008-11-05 Thread pilar schneider 
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
  3.22761140.1223412   -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   3.4141050.069387   -0.0006836
2   3.2276114   0.1223412  -0.0006836

n      ..   .
THANKS FOR YOUR HELP

Maria

-- 
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[EMAIL PROTECTED]

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

2008-11-05 Thread 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
   3.22761140.1223412   -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   3.4141050.069387   -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.
NDRI, Inc. (www.ndri.org)
71 West 23rd Street, 8th floor
New York, NY 10010
tel: (212) 845-4495 (Tu, Th)
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Re: [R] how can I save the estimates of a regression model in a file?

2008-11-05 Thread hadley wickham 
On Wed, Nov 5, 2008 at 11:12 AM, pilar schneider
[EMAIL PROTECTED] 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))


Here's one way that uses the plyr package (http://had.co.nz/)

# Name the model fitting function
fit_model - function(df) lm(logmilk ~ logdays + days, data = df)

# Create a list of models for each value of V2
# this is basically equivalent to by, but it deals with labelling a bit better
models - dlply(data2, .(V2), fit_model)

# Produce a data frame containing the coefficients for each model
ldply(models, coef)

Hadley


-- 
http://had.co.nz/

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PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.