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adding layers in ggplot2 (data and code included)

3 messages · Juliet Hannah, eric, Hadley Wickham

Juliet Hannah
# 
Here is some sample data:

mydata <- read.table(textConnection("Est Group    Tri
       0        0 4.639644
       1        0 4.579189
       2        0 4.590714
       0        1 4.443696
       1        1 4.588243
       2        1 4.650505
       0        2 4.296608
       1        2 4.826036
       2        2 4.765386"),header=TRUE);
  closeAllConnections();

I can form two plots, scatter and  lines, as follows:

p <- ggplot(mydata, aes(x=Est, y=Tri))
p + geom_point(aes(colour=factor(Group),shape=factor(Group)))

and

p+ geom_smooth(aes(group=factor(Group),color=factor(Group)),method=lm,se=F).

However, I am unable to have the plots together.

I obtain the following error:
Error in `[.data.frame`(df, , var) : undefined columns selected

Thanks,

Juliet
eric
# 
The way you've attempted to get this result seems to align with the way 
R "should" work, but it fails in this case.
The fix is to break things up a little bit:

p <- ggplot(mydata, aes(x=Est, y=Tri))
p <- p + geom_point(aes(colour=factor(Group),shape=factor(Group)))
p <- p + 
geom_smooth(aes(group=factor(Group),color=factor(Group)),method=lm,se=F)
p


Eric
Juliet Hannah wrote:
Hadley Wickham
# 
Hi Juliet,
On Sun, Sep 21, 2008 at 11:47 PM, Juliet Hannah <juliet.hannah at gmail.com> wrote:
Are you using R 2.7.2?  Something in R changed between R 2.7.1 and R
2.7.2 that breaks certain ggplot plots (you code works fine for me
without modification).  It's on my to do list to fix.

You can also simplify your code a little by relying on defaults set in
the ggplot() call:

ggplot(mydata, aes(Est, Tri, colour = factor(Group))) +
 geom_point(aes(shape = factor(Group))) +
 geom_smooth(method = lm, se = F)

(Andpleaseusespacesotherwiseitsveryhardtoreadyourcode)

Hadley