> From: Greg Snow > > >>> "BANNISTER, Keith" <[EMAIL PROTECTED]> 09/20/05 > 09:46AM >>> > >> > >> Hi, > >> > >> I'd like to use R to do what excel pivot tables do, and plot > results. > > R does not have pivot tables and I hope that it never does. > > My experiance with pivot tables is that they encourage poor initial > design followed > by non-easily-reproducable post-hoc twiddling. > > R encourages proper initial design followed by fixing the core design > in cases > where things don't turn out the way you intended. > > In R I prefer to work with script files and save the file. If the > table or graph > does not turn out the way I intended, then I just edit the script file > and rerun it. > While this may be a little more work than clicking on a pivot table at > first, in the > long run I find it saves more time.
Actually, it's even better to write functions for repetitive tasks. This is one of the things Martin talked about at useR! 2004: http://www.ci.tuwien.ac.at/Conferences/useR-2004/Keynotes/Maechler.pdf For Keith's problem, here's one possibility (using plotCI() from gplots): myErrorBarPlot <- function(SNR, timeError, ...) { stopifnot(require(gplots)) m <- aggregate(timeError, list(SNR), mean) d <- aggregate(timeError, list(SNR), sd) dat <- cbind(m, d[, 2]) names(dat) <- c("SNR", "mean", "sd") dat$SNR <- as.numeric(as.character(dat$SNR)) with(dat, plotCI(SNR, mean, uiw=3*sd, ...)) invisible(dat) } vn <- read.table("clipboard", header=TRUE) myErrorBarPlot(vn$SNR, vn$timeError) Andy > Consider the situation where you create a table/graph, then a month > later your > boss/client/coworker finds some typos in the original data and needs > the table > and/or graph recreated with the corrected data (or maybe a new dataset > that > needs a similar graph/table). With the pivot table you need > to try and > remember > everything that you clicked on and click on it again. With the R > script file you > just fix the data (or load in the new data) and rerun the script and > your done. > > OK, enough of my ranting, on to helping with your problem. > > > >> I've never used R before, and I've managed to do > something, but it's > quite a > >> lot of code to do something simple. I can't help but think I'm not > "Doing it > >> the R way". > >> > >> I could be using R for the wrong thing, in which case, please tell > me off. > [snip] > > "by" is a bit of an overkill for this situation, tapply will probably > work better. > > try this basic script as a starting place: > > ### start ### > my.df <- data.frame( SNR=rep( c(4,6,8), each=3), > timeError = c(1.3,2.1,1.2,2.1,2.2,2.1,3.2,3.7,3.1)) > > tmp.mean <- tapply( my.df$timeError, my.df$SNR, mean) > tmp.sd <- tapply( my.df$timeError, my.df$SNR, sd) > > tmp.x <- unique(my.df$SNR) > > plot( tmp.x, tmp.mean, > ylim=range(tmp.mean+3*tmp.sd,tmp.mean-3*tmp.sd), > xlab='SNR',ylab='timeError') > > segments(tmp.x, tmp.mean-3*tmp.sd, tmp.x, tmp.mean+3*tmp.sd, > col='green') > > ### optional > points(tmp.x, tmp.mean+3*tmp.sd, pch='-',cex=3,col='green') > points(tmp.x, tmp.mean-3*tmp.sd, pch='-',cex=3,col='green') > points(tmp.x, tmp.mean) > > ### end script ### > > This may be even simpler with a loaded package. a quick search shows > the following functions (package in parens) that may help: > > plotCI(gplots) Plot Error Bars and Confidence Intervals > errbar(Hmisc) Plot Error Bars > xYplot(Hmisc) xyplot and dotplot with Matrix Variables to > Plot Error Bars and Bands > > plotCI(plotrix) Plot confidence intervals/error bars > > errbar(sfsmisc) Scatter Plot with Error Bars > plotCI(sfsmisc) Plot Confidence Intervals / Error Bars > > > > > >> Appreciate any helpful hints from the pros. > >> > > hope this helps, > > >> Cheers! > >> > >> p.s. We've been having rather a good time around the > office recently > with > >> "International Talk Like a Pirate Day" (www.yarr.org.uk). R fits in > very > >> well: "I be usin' Arrrgghhhh for my post processin'". > >> > >> > >> Keith Bannister > > > Greg Snow, Ph.D. > Statistical Data Center, LDS Hospital > Intermountain Health Care > [EMAIL PROTECTED] > (801) 408-8111 > > ______________________________________________ > R-help@stat.math.ethz.ch mailing list > https://stat.ethz.ch/mailman/listinfo/r-help > PLEASE do read the posting guide! > http://www.R-project.org/posting-guide.html > > > ______________________________________________ R-help@stat.math.ethz.ch mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html
