From: Sean O'Riordain <sean.oriordain_at_gmail.com>

Date: Tue 16 Aug 2005 - 16:36:26 EST

)

#dev.off()

}

https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html Received on Tue Aug 16 16:42:40 2005

Date: Tue 16 Aug 2005 - 16:36:26 EST

Sander,

consider writing a function to do your plotting, then pass in the dataframe name so... something along the lines of...

*# create a function which takes two arguments
*

# mydf - a dataframe of a particular format... eg. the abc column is number 4

# i the column we want to aggregate and plot this time around...

myplotfn <- function(mydf,i) {

# body of the function

# extract the relevant column - i

colval <- mydf[3+i]

tmp <- aggregate(colval, list(

mydf$bins, mydf$groups),

mean)

# grab the name of the column we're working on; eg. "abc"
colnam.r <- names(mydf)[3+i]

colnames(tmp) <- c("bins", "groups", colnam.r)
tmp

#pltName <- paste("line_datGrassChem_", colnam.r, ".eps", sep="")
#postscript(pltName)

labs <- c("-15/-9","-9/-6","-6/-3","-3/0")
sps <- trellis.par.get("superpose.symbol")
sps$pch <- 1:4

trellis.par.set("superpose.symbol", sps) # create the proper formula for plotting something like "abc ~ bins" myformula <- as.formula(paste(colnam.r, "~ bins")) xyplot( myformula, data = tmp, groups = groups, type = list("p", "l"), scales = list(x = list(labels=labs)), layout = c(1,1), key = list(columns = 4, text = list(paste(unique(tmp$groups))), points = Rows(sps, 1:4) )

)

#dev.off()

}

# then call it by

myplotfn(test,1) myplotfn(test,2) myplotfn(test,3)

obviously this can be put in a loop :-)

So how did I figure out how to do this? well in the introduction manual it talks about functions... the tricky bit was the substitution of abc into the relevant places...

I didn't know how to convert the string formula "abc ~ bins" into a
formula that I could plot, so first off, I looked at ?plot, in there
it mentioned ?plot.formula and in there it mentioned the class formula
so I said ?formula where it mentioned as.formula()... bingo... this
allowed me to say

myformula <- as.formula("abc ~ bins")

So I made this into a "learning experience" for me :-)

I'm relatively new to R... so giving myself little problems like this is a good way of learning R... and hopefully helping somebody else! :-)

I'm pretty sure that there is a better way of doing this in R - but this works :-)

cheers

Sean

On 15/08/05, Sander Oom <slist@oomvanlieshout.net> wrote:

> Dear all, > > I have a data frame containing the results of an experiment. Like this: > > a<-seq(1,4,by=1) > b<-seq(1,2,by=1) > test<-expand.grid(b,a,a) > colnames(test)<-c("replicates","bins", "groups") > test$abc <- rnorm(32) > test$def <- rnorm(32) > test$ghi <- rnorm(32) > test > > The following code snippet aggregates the data for one variable and then > draws a plot: > > tmp <- aggregate(test$abc, list( > test$bins, test$groups), > mean) > colnames(tmp) <- c("bins", "groups", "abc") > tmp > #pltName <- paste("line_datGrassChem_", "abc", ".eps", sep="") > #postscript(pltName) > labs <- c("-15/-9","-9/-6","-6/-3","-3/0") > sps <- trellis.par.get("superpose.symbol") > sps$pch <- 1:4 > trellis.par.set("superpose.symbol", sps) > xyplot( abc ~ bins, data = tmp, > groups = groups, type = list("p", "l"), > scales = list(x = list(labels=labs)), > layout = c(1,1), > key = list(columns = 4, > text = list(paste(unique(tmp$groups))), > points = Rows(sps, 1:4) > ) > ) > #dev.off() > > How can I wrap R code around this code snippet, such that I can repeat > the same code snippet for all other variables in the data frame (i.e. > def, ghi, etc.). > > Thanks for your suggestions! > > Sander. > > -- > -------------------------------------------- > Dr Sander P. Oom > Animal, Plant and Environmental Sciences, > University of the Witwatersrand > Private Bag 3, Wits 2050, South Africa > Tel (work) +27 (0)11 717 64 04 > Tel (home) +27 (0)18 297 44 51 > Fax +27 (0)18 299 24 64 > Email sander@oomvanlieshout.net > Web www.oomvanlieshout.net/sander > > ______________________________________________ > 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 Received on Tue Aug 16 16:42:40 2005

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