With stat="summary", fun.y="mean" get "Each group consist of only one observation"

[Etienne Low-Decarie]

I have a script that has the form

d <- qplot(cyl, mpg, data=mtcars)

d + geom_line(stat="summary", fun.y="mean")

Which now produces

"geom_path: Each group consist of only one observation. Do you need to adjust the group aesthetic?"

I am running ggplot2 0.9.2.99 on R  2.15.2

This used to work.  Any suggestions?

Thank you so much for the incredible package!

[Etienne Low-Decarie]

To be more precise, my code is more of the form

d <- qplot(qsec, mpg, data=mtcars, colour=as.character(cyl), shape=as.character(gear))

d + geom_line(stat="summary", fun.y="mean", aes(group=as.character(cyl)))

So just using:

stat_sum_single <- function(fun, geom="point", ...) { stat_summary(fun.y=fun, colour="red", geom=geom, size = 3, ...) }

Does not seem to work.

[Etienne Low-Decarie]

stat_sum_single <- function(fun, geom="point", ...) {

  stat_summary(fun.y=fun, colour="red", geom=geom, size = 3, ...)

}

d + stat_sum_single(mean, geom="line", aes(group=as.character(cyl)))

Also gives 

[Dennis Murphy]

d <- qplot(qsec, mpg, data=mtcars, colour=as.character(cyl),
shape=as.character(gear))

d + stat_summary(fun.y = mean, geom = "line",
aes(group = as.character(cyl))) +
labs(colour = "cyl", shape = "gear")

Is that what you were after?
Dennis

[Etienne Low-Decarie]

This also produces geom_path: Each group consist of only one observation. Do you need to adjust the group aesthetic?  with no path being plotted.

Thank you

library(ggplot2)

> d <- qplot(qsec, mpg, data=mtcars, colour=as.character(cyl), 

+            shape=as.character(gear)) 

> d + stat_summary(fun.y = mean, geom = "line", 

+                  aes(group = as.character(cyl))) + 

+                      labs(colour = "cyl", shape = "gear") 

geom_path: Each group consist of only one observation. Do you need to adjust the group aesthetic?

[Winston Chang]

I think the following _should_ work, but doesn't:

ggplot(mtcars, aes(x=cyl, y=mpg)) +

  geom_point() +

  stat_summary(fun.y=mean, geom="line", aes(group=factor(cyl)))

This may be a bug in the new version. Could you file an issue on github?

https://github.com/hadley/ggplot2/issues

-Winston

--
You received this message because you are subscribed to the ggplot2 mailing list.
Please provide a reproducible example: https://github.com/hadley/devtools/wiki/Reproducibility
 
To post: email ggp...@googlegroups.com
To unsubscribe: email ggplot2+u...@googlegroups.com
More options: http://groups.google.com/group/ggplot2

[Morten Lindow]

I would be grateful if any would share a solution to this problem.  Thanks!

Morten

[Dennis Murphy]

Since the stat_summary() examples in the current documentation
indicate the same error message, the safe thing to do in the interim
is probably to do the summarization outside of ggplot2 in a separate
data frame and then use it in the layers where you need it.

Here is an example for a simple interaction plot:

library(ggplot2)
library(plyr)

# Produce a data frame of mean(mpg) for vs/am combinations
mtm <- ddply(mtcars, .(vs, am), summarise, mn = mean(mpg))

# interaction plot
ggplot(mtm, aes(x = factor(vs), y = mn, group = factor(am))) +
geom_point(size = 3) + geom_line()


# The error message appears if I try something like this in 0.9.3:

ggplot(mtcars, aes(x = factor(vs), y = mpg) +
stat_summary(fun.y = mean, aes(group = factor(am)),
geom = "point", size = 3) +
stat_summary(fun.y = mean, aes(group = factor(am)),
geom = "line", size = 1)

The first stat_summary() call works, but not the second.

I looked around yesterday for open or closed issues on GitHub
regarding this topic, but didn't find one, so I don't know offhand if
this has been fixed in the development version or not.

Dennis

On Thu, Jan 10, 2013 at 12:05 AM, Morten Lindow <morten...@gmail.com> wrote:
> I would be grateful if any would share a solution to this problem. Thanks!
>
> Morten
>

[Bryan Hanson]

It's issue 739.

Also, it seems all issues have been closed. Am I looking in the right place?

https://github.com/hadley/ggplot2/issues?milestone=1&page=2&state=closed

Thanks, Bryan

(and thanks Dennis for a suggested fix)

[Brandon Hurr]

Bryan, you had a filter on... 

https://github.com/hadley/ggplot2/issues?labels=&milestone=&page=1&state=open

[Bryan Hanson]

Thanks all.  I knew it didn't look right!