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
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