Re: [R] Running different Regressions using for loops

Krunal Nanavati Wed, 26 Sep 2012 23:34:44 -0700

Dear Rui,



Thanks for your time.



I have a question though, when I run the 5 regression, whose outputs are
stored in lm.list[i], I only get the coefficients for the Intercept,
Price, Trend & Seasonality as below



> lm.list[1]

[[1]]



Call:

lm(formula = as.formula(fmla), data = tryout)



Coefficients:

(Intercept)       Price4        Trend  Seasonality

    9923123     -2606826        64616       551392



I am also looking out for t stats and p value and R squared. Do you know,
how can I get all these statistics. Also, why is  as.formula  used in the
lm function. It should work without that as well, right?



Can you please tell me, why the code that I had written, does not work with
R. I thought it should work perfectly.



Thanks & Regards,



Krunal Nanavati

9769-919198



*From:* Rui Barradas [mailto:ruipbarra...@sapo.pt]
*Sent:* 26 September 2012 17:13
*To:* Krunal Nanavati
*Cc:* r-help@r-project.org
*Subject:* Re: [R] Running different Regressions using for loops



Hello,

Try the following.


#cnames <- names(tryout)  # in your code, use this one
cnames <- c("Volume", "Price1", "Price2", "Price3", "Price4", "Price5",
"Trend", "Seasonaliy")

price <- cnames[grep("Price", cnames)]
resp <- cnames[1]
regr <- cnames[7:8]

#lm.list <- vector("list", 5)
for(i in 1:5){
    regress <- paste(price[i], paste(regr, collapse = "+"), sep = "+")
    fmla <- paste(resp, regress, sep = "~")
    print(fmla)
    #lm.list[[i]] <- lm(as.formula(fmla), data = tryout)
}

Hope this helps,

Rui Barradas

Em 26-09-2012 08:08, Krunal Nanavati escreveu:

Hi,







I am trying to run many different regressions using a FOR Loop.







The input data that is read into R has the following variables







·         Volume



·         Price1



·         Price2



·         Price3



·         Price4



·         Price5



·         Trend



·         Seasonality







I want to run 5 regressions, with the Volume as an dependent variable and

Price, Trend & Seasonality as independent variables. I have read the above

mentioned variables in a variable called tryout







I am entering the following syntax in R







for(i in 1:5)



+ {



+ result[i]=lm(Volume~Price[i]+Trend+Seasonaliy,data=tryout)



+ summary(result[i])



+ }







After running these linesI am getting the following error message







Error in eval(expr, envir, enclos) : object 'Price' not found







Can someone help me out with this error message. Appreciate for your time

and consideration.















Thanks & Regards,







Krunal Nanavati



Solutions Manager - Cogitaas



9769-919198



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