[R] plot separate groups with plotmeans()

[Bart Toonen]

Hi,

This answer may be a bit overdue, but I had a similar problem and it took 
me quite some time to find a good solution. When searching with google, 
your post kept showing up, so I post this to help others.
The command that worked for me was interaction.plot. 
Example:
x <- data.frame(Score=rnorm(100), Time=rep(1:5, 
20),Group=factor(rep(c("A","B"),50)))
interaction.plot(x$Group,x$Time,x$Score)

Note, I used 5 Time groups; with 10 groups, no lines showed up.


Bart.

Op woensdag 9 november 2011 01:19:54 UTC+1 schreef Jon Zadra het volgende:
>
> Hi,
>
> I often use plotmeans() from the gplots package to quickly visualize a 
> pattern of change.  I would like to be able to plot separate lines for 
> different groups, but the function gives an error when a grouping 
> variable is included in the formula argument.
>
> For instance,
>  > require(gplots)
>  > x <- data.frame(Score=rnorm(100), Time=rep(1:10, 10), 
> Group=factor(rep(c("A","B"),50)))
>  > plotmeans(Score ~ Time, x) #works fine
>  > plotmeans(Score ~ Time * Group, x)
> Error in .subset2(x, i, exact = exact) :
>    attempt to select more than one element
>  > plotmeans(Score ~ Time | Group, x)
> Error in ns - 1 : non-numeric argument to binary operator
> In addition: Warning message:
> In Ops.factor(Time, Group) : | not meaningful for factors
>
> The help for plotmeans() states that it accepts a formula object 
> including a grouping variable.  There is no other grouping argument 
> listed.  Any help is appreciated, including pointing to a more robust 
> function for plotting means.
>
> Thanks,
>
> Jon
> -- 
> Jon Zadra
> Department of Psychology
> University of Virginia
> P.O. Box 400400
> Charlottesville VA 22904
> (434) 982-4744
> email: za... at virginia.edu <javascript:>
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