[R] ggplot2 used in a function - variable scope/environment

From: Martin Rittner <martin.rittner_at_thegeologician.net>
Date: Fri, 15 Feb 2008 20:21:08 +0000


Hi everybody!

I'm trying to use ggplot2 to return a plot from a function (so I can add something or alter it then). Unfortunately, if I add a mapping to a layer in the function, the variable *name* is stored in the layer, rather than the variable's *value* - so that after the function returns the ggplot2-object, it doesn't plot because the variable don't exist in the environment calling the function.. e.g:

my function does something like:

getPlot<-function(da=NULL,...){

	#1st column holds x-values, others hold data series to plot...
	co<-as.character(names(da))
	co<-co[2:length(co)]

	pl<-ggplot(data=da)
	pl<-pl+scale_y_log10()+scale_x_continuous()
	for(c in co){
		pl<-pl+geom_line(x=da[[1]],y=da[[c]],mapping=aes(x=da[[1]],y=da[[c]]))
	}

	return(pl)

}

I need to add every layer separately, because I want to be able to explicitly define attributes for every data series (colour, size... e.g. highlight only two specific out of 10 series...).

Anyway, my problem is this:

d<-data.frame(x=seq(0.0,1.0,length=5),y1=rnorm(5),y2=rnorm(5)) p<-getPlot(da=d)
p

returns with

Error in data.frame(..., check.names = FALSE) :

   arguments imply differing number of rows: 0, 5

and the plot object contains:

Title:
Labels: x=, y=



Data: x, y1, y2 [5x3]
Mapping:
Scales: y,x -> y,x
$margins
[1] FALSE $facets
[1] ". ~ ."

geom_line: (colour=black, size=1, linetype=1, x=NA, y=NA) + (x=c(0, 0.25, 0.5, 0.75, 1), y=c(0.180036717548597, -0.369556903134046,
-0.924474152821948, -2.40773640658189, 0.801471591443009))
stat_sort: (...=) + (x=c(0, 0.25, 0.5, 0.75, 1), y=c(0.180036717548597,
-0.369556903134046, -0.924474152821948, -2.40773640658189,
0.801471591443009))
position_identity: ()
mapping: (x=da[[1]], y=da[[c]])

geom_line: (colour=black, size=1, linetype=1, x=NA, y=NA) + (x=c(0, 0.25, 0.5, 0.75, 1), y=c(-1.59744511956184, -0.9333541477049, 1.88697835844878, 0.921829569181679, -0.741077741846118)) stat_sort: (...=) + (x=c(0, 0.25, 0.5, 0.75, 1), y=c(-1.59744511956184,
-0.9333541477049, 1.88697835844878, 0.921829569181679, -0.741077741846118))
position_identity: ()
mapping: (x=da[[1]], y=da[[c]])

Note the mappings, they refer to "da" and "c" (defined in the function) which are not available in the calling environment. Any Idea how I can avoid the problem/paste the actual values in, like it did for the geometry and the statistics?

Thanks, Martin



R-help_at_r-project.org mailing list
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. Received on Fri 15 Feb 2008 - 20:49:43 GMT

Archive maintained by Robert King, hosted by the discipline of statistics at the University of Newcastle, Australia.
Archive generated by hypermail 2.2.0, at Fri 15 Feb 2008 - 21:30:14 GMT.

Mailing list information is available at https://stat.ethz.ch/mailman/listinfo/r-help. Please read the posting guide before posting to the list.

list of date sections of archive