Thank you very much, Marc & Bert. Bert - I think you're correct. With Marc's solution, I am not able to get the response variable name in the call to lm(). But, your solution works well.
Best regards, Ravi -----Original Message----- From: Bert Gunter [mailto:bgunter.4...@gmail.com] Sent: Tuesday, October 27, 2015 1:50 PM To: Ravi Varadhan <ravi.varad...@jhu.edu> Cc: r-help@r-project.org Subject: Re: [R] How to get variable name while doing series of regressions in an automated manner? Marc,Ravi: I may misunderstand, but I think Marc's solution labels the list components but not necessarily the summary() outputs. This might be sufficient, as in: > z <- list(y1=rnorm(10,5),y2 = rnorm(10,8),x=1:10) > > ##1 > results1<-lapply(z[-3],function(y)lm(log(y)~x,data=z)) > lapply(results1,summary) $y1 Call: lm(formula = log(y) ~ x, data = z) Residuals: Min 1Q Median 3Q Max -0.2185 -0.1259 -0.0643 0.1340 0.3988 Coefficients: Estimate Std. Error t value Pr(>|t|) (Intercept) 1.69319 0.14375 11.779 2.47e-06 *** x -0.01495 0.02317 -0.645 0.537 --- Signif. codes: 0 ‘***’ 0.001 ‘**’ 0.01 ‘*’ 0.05 ‘.’ 0.1 ‘ ’ 1 Residual standard error: 0.2104 on 8 degrees of freedom Multiple R-squared: 0.04945, Adjusted R-squared: -0.06937 F-statistic: 0.4161 on 1 and 8 DF, p-value: 0.5369 $y2 Call: lm(formula = log(y) ~ x, data = z) Residuals: Min 1Q Median 3Q Max -0.229072 -0.094579 -0.006498 0.134303 0.188158 Coefficients: Estimate Std. Error t value Pr(>|t|) (Intercept) 2.084846 0.104108 20.026 4.03e-08 *** x -0.006226 0.016778 -0.371 0.72 --- Signif. codes: 0 ‘***’ 0.001 ‘**’ 0.01 ‘*’ 0.05 ‘.’ 0.1 ‘ ’ 1 Residual standard error: 0.1524 on 8 degrees of freedom Multiple R-squared: 0.01692, Adjusted R-squared: -0.106 F-statistic: 0.1377 on 1 and 8 DF, p-value: 0.7202 ## 2 Alternatively, if you want output with the correct variable names, bquote() can be used, as in: > results2 <-lapply(names(z)[1:2], + function(nm){ + fo <-formula(paste0("log(",nm,")~x")) + eval(bquote(lm(.(u),data=z),list(u=fo))) + }) > lapply(results2,summary) [[1]] Call: lm(formula = log(y1) ~ x, data = z) Residuals: Min 1Q Median 3Q Max -0.2185 -0.1259 -0.0643 0.1340 0.3988 Coefficients: Estimate Std. Error t value Pr(>|t|) (Intercept) 1.69319 0.14375 11.779 2.47e-06 *** x -0.01495 0.02317 -0.645 0.537 --- Signif. codes: 0 ‘***’ 0.001 ‘**’ 0.01 ‘*’ 0.05 ‘.’ 0.1 ‘ ’ 1 Residual standard error: 0.2104 on 8 degrees of freedom Multiple R-squared: 0.04945, Adjusted R-squared: -0.06937 F-statistic: 0.4161 on 1 and 8 DF, p-value: 0.5369 [[2]] Call: lm(formula = log(y2) ~ x, data = z) Residuals: Min 1Q Median 3Q Max -0.229072 -0.094579 -0.006498 0.134303 0.188158 Coefficients: Estimate Std. Error t value Pr(>|t|) (Intercept) 2.084846 0.104108 20.026 4.03e-08 *** x -0.006226 0.016778 -0.371 0.72 --- Signif. codes: 0 ‘***’ 0.001 ‘**’ 0.01 ‘*’ 0.05 ‘.’ 0.1 ‘ ’ 1 Residual standard error: 0.1524 on 8 degrees of freedom Multiple R-squared: 0.01692, Adjusted R-squared: -0.106 F-statistic: 0.1377 on 1 and 8 DF, p-value: 0.7202 HTH or apologies if I've missed the point and broadcasted noise. Cheers, Bert Bert Gunter "Data is not information. Information is not knowledge. And knowledge is certainly not wisdom." -- Clifford Stoll On Tue, Oct 27, 2015 at 8:19 AM, Ravi Varadhan <ravi.varad...@jhu.edu> wrote: > Hi, > > I am running through a series of regression in a loop as follows: > > results <- vector("list", length(mydata$varnames)) > > for (i in 1:length(mydata$varnames)) { results[[i]] <- > summary(lm(log(eval(parse(text=varnames[i]))) ~ age + sex + > CMV.status, data=mydata)) } > > Now, when I look at the results[i]] objects, I won't be able to see the > original variable names. Obviously, I will only see the following: > > Call: > lm(formula = log(eval(parse(text = varnames[i]))) ~ age + sex + CMV.status, > data = mydata) > > > Is there a way to display the original variable names on the LHS? In > addition, is there a better paradigm for doing these type of series of > regressions in an automatic fashion? > > Thank you very much, > Ravi > > Ravi Varadhan, Ph.D. (Biostatistics), Ph.D. (Environmental Engg) > Associate Professor, Department of Oncology Division of Biostatistics > & Bionformatics Sidney Kimmel Comprehensive Cancer Center Johns > Hopkins University > 550 N. Broadway, Suite 1111-E > Baltimore, MD 21205 > 410-502-2619 > > > [[alternative HTML version deleted]] > > ______________________________________________ > R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see > https://stat.ethz.ch/mailman/listinfo/r-help > PLEASE do read the posting guide > http://www.R-project.org/posting-guide.html > and provide commented, minimal, self-contained, reproducible code. ______________________________________________ R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
