R help - Mar 2008 - hello! i need help for a specific graphic issue

hello, ladyes and gentlemans.

check this:

means<-c(4,6,8)
stand.error<-c(0.1,0.3,0.5)

now i've strongly tryed to scatterplot the
means(y-axis),by showing their sd with the
arrow(..,code=3,angle=90) function.
The problem is that my x-axis has categorical values
(say, factor(x)), and the arrows() can't recognize
them as right coordinates.
?????
thank you all in advance
B.F. insubria university (varese)



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hi Giacomo,

consider this:

means<-c(4,6,8)
stand.error<-c(0.1,0.3,0.5)
lowlim<-means-stand.error
uplim<-means+stand.error
plot(as.factor(c("a","b","c")),means,ylim=c(min(lowlim),max(uplim)))
arrows(c(1:3),lowlim,c(1:3),uplim,code=3,angle=90)

Still, its just a workaround and I don't think you can get rid of the
horizontal mean-lines because this is actually a box-plot.
Otherwise you could try the 'errbar()' from the Hmisc package. I never
used that, but maybe it works.
Generally, if you have problems with plot-dimensions, you can get instant
information with 'locator()', which returns coordinates of mouse clicked
locations in plots.

cheers, /ren?

> -----Urspr?ngliche Nachricht-----
> Von: "Giacomo Prodi" <bonoricus at yahoo.it>
> Gesendet: 12.03.08 11:56:45
> An: r-help at r-project.org
> Betreff: [R] hello! i need help for a specific graphic issue
> 
> hello, ladyes and gentlemans.
> 
> check this:
> 
> means<-c(4,6,8)
> stand.error<-c(0.1,0.3,0.5)
> 
> now i've strongly tryed to scatterplot the
> means(y-axis),by showing their sd with the
> arrow(..,code=3,angle=90) function.
> The problem is that my x-axis has categorical values
> (say, factor(x)), and the arrows() can't recognize
> them as right coordinates.
> ?????
> thank you all in advance
> B.F. insubria university (varese)
> 
> 
> 
> La web mail pi? usata al mondo.
http://it.docs.yahoo.com/mail/overview/index.html
> 
> ______________________________________________
> 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.
> 

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On Wed, Mar 12, 2008 at 5:37 AM, Giacomo Prodi <bonoricus at yahoo.it>
wrote:
> hello, ladyes and gentlemans.
>
>  check this:
>
>  means<-c(4,6,8)
>  stand.error<-c(0.1,0.3,0.5)
>
>  now i've strongly tryed to scatterplot the
>  means(y-axis),by showing their sd with the
>  arrow(..,code=3,angle=90) function.
>  The problem is that my x-axis has categorical values
>  (say, factor(x)), and the arrows() can't recognize
>  them as right coordinates.
>  ?????
>  thank you all in advance
>  B.F. insubria university (varese)
This is a bit easier to do with ggplot2:

df <- data.frame(
  trt = factor(c("a", "b", "c")),
  mean = c(4,6,8),
  se = c(0.1,0.3,0.5)
)

install.packages("ggplot2")
library(ggplot2)

qplot(trt, mean, data=df)
qplot(trt, mean, data=df, min=mean - se, max = mean + se,
geom="pointrange")

Hadley

-- 
http://had.co.nz/

quick (and dirty) solution:

y.up<- means+stand.error
y.dwn<- means-stand.error

plot(means,ylim=c(3.5,10))
for (i in 1:length(means)) arrows(i,means[i],i,y.up[i],length=0.1)
for (i in 1:length(means)) arrows(i,means[i],i,y.dwn[i],length=0.1)




Giacomo Prodi wrote:
> 
> hello, ladyes and gentlemans.
> 
> check this:
> 
> means<-c(4,6,8)
> stand.error<-c(0.1,0.3,0.5)
> 
> now i've strongly tryed to scatterplot the
> means(y-axis),by showing their sd with the
> arrow(..,code=3,angle=90) function.
> The problem is that my x-axis has categorical values
> (say, factor(x)), and the arrows() can't recognize
> them as right coordinates.
> ?????
> thank you all in advance
> B.F. insubria university (varese)
> 
> 
> 
> La web mail pi? usata?al mondo.
> http://it.docs.yahoo.com/mail/overview/index.html
> 
> ______________________________________________
> 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.
> 
> 
-- 
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I don't think that you're actually creating a
scatterplot if the x-axis is a factor.  You're getting
a boxplot.

If you want a scatterplot then something like this
might work.
=====================================================
means<-c(4,6,8)
stand.error<-c(0.1,0.3,0.5)

aa <- factor(c("A","B","C","A",
"C", "C"))
dd <- 1:length(levels(aa))

plot(dd, means, xaxt="n") 
arrows(dd, means + stand.error, dd, means-stand.error,
          code=3, angle=90)
axis(1, at=dd, labels=levels(aa))

======================================================
--- Giacomo Prodi <bonoricus at yahoo.it> wrote:
> hello, ladyes and gentlemans.
> 
> check this:
> 
> means<-c(4,6,8)
> stand.error<-c(0.1,0.3,0.5)
> 
> now i've strongly tryed to scatterplot the
> means(y-axis),by showing their sd with the
> arrow(..,code=3,angle=90) function.
> The problem is that my x-axis has categorical values
> (say, factor(x)), and the arrows() can't recognize
> them as right coordinates.
> ?????
> thank you all in advance
> B.F. insubria university (varese)
> 
> 
> 
> La web mail pi? usata al mondo.
> http://it.docs.yahoo.com/mail/overview/index.html
> 
> ______________________________________________
> 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.
>