[R] ggplot - class "character" problem

[Ista Zahn]

Hi David,

On Tue, Sep 13, 2011 at 6:00 AM, David Menezes
<david.n.menezes at gmail.com> wrote:
> Hi
>
> I'm trying to use ggplot2 to chart a dataset that I've drawn in from
> excel.  When I run the qplot command, I get the following error
> message:
>
> Error: ggplot2 doesn't know how to deal with data of class character
>
>
> It feels like I need to coerce one of the fields in my data frame.
> Here's the code, which is short:
>
> #draw data in from network location
> setwd("S:\\790\\Actuarial\\KFC\\609 Kernel\\Sensitivity
> Tests\\Stressed ESG inputs")
> input<-read.csv("yieldcurve plus 1pct abs.csv",header=FALSE)
>
> #label columns
> colnames(input)<-c("scenID","yrs_ahead",0.5,1.0,2.0,3.0,4.0,5.0,6.0,7.0,8.0,9.0,10.0,11.0,12.0)
>
> #create a data frame that i hope! will work with ggplot..
> flat_data<-data.frame(cbind(input[1:2],stack(input[3:15])))
> colnames(flat_data)<-c("scenID","yrs_ahead","yield","time")
>
> #plot
> library(ggplot2)
> qplot(time,yield,data="flat_data",facets = yrs_ahead~.)

Try dropping the quotes from "flat_data", i.e.,

qplot(time, yield, data=flat_data, facets = yrs_ahead~.)

Best,
Ista

>
> now the error.
>
> In terms of the data format, head(flat data) returns the following:
>
>> head(flat_data)
>  scenID yrs_ahead      yield time
> 1      1         0 0.01637218  0.5
> 2      1         1 0.02446376  0.5
> 3      1         2 0.04501267  0.5
> 4      1         3 0.06947724  0.5
> 5      1         4 0.08262982  0.5
> 6      1         5 0.09761927  0.5
>
> 1) Am I right that it's about coercion of variable type?
> 2) Any ideas how to proceed?
>
> Many thanks,
> Dave
>
> ______________________________________________
> 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.
>



-- 
Ista Zahn
Graduate student
University of Rochester
Department of Clinical and Social Psychology
http://yourpsyche.org