[R] Scatterplot with data grouped by color

[Martin Maechler]

>>>>> "JIV" == Jorge Ivan Velez <jorgeivanvelez at gmail.com>
>>>>>     on Fri, 12 Sep 2008 18:39:04 -0400 writes:

    JIV> Dear Amanda,
    JIV> Try this:

    JIV> # Data set
    JIV> set.seed(123)
    JIV> DF=data.frame(A=rnorm(10),B=rpois(10,10),C=sample(1:3,10,replace=T))
    JIV> attach(DF)

    JIV> # Plot
    JIV> plot(A,B,pch=16,col=C)
    JIV> legend('topleft',paste('Group',1:3,sep=" "),col=1:3,pch=16)

    JIV> HTH,

Yes, that's a fine small example.

To become flawless (in the eyes of the R-stylepolice :-)),
you'd have to *NOT* attach() the data frame 
{= a bad habit from earlier implementations of the S language and R},
but rather either use with(.) , or often (as in this case),
just specify  a 'data= . ' :

 # Data set
 set.seed(123)
 DF <- data.frame(A=rnorm(10),B=rpois(10,10),C=sample(1:3,10,replace=T))

 # Plot
 plot(B ~ A, pch=16, col=C, data = DF)
 legend('topleft',paste('Group',1:3,sep=" "),col=1:3,pch=16)


Regards,
Martin


    JIV> On Fri, Sep 12, 2008 at 6:29 PM, Amanda Young <amandag at mit.edu> wrote:

    >> Hi,
    >> I am a complete R rookie so this question is probably really simple
    >> but I haven't found an answer on the web that I can understand.
    >> 
    >> My data frame has 3 columns, A, B and C. A and B have numbers (about
    >> 8000 rows), C is a factor which is either true or false. So I can
    >> plot A vs B with plot(dataframe$A, dataframe$B). However, I would
    >> like the points to be different colors depending on whether C is True
    >> or False. Even better, if C had more than 2 groups, like group 1,2,3
    >> can I make all 3 different colors, etc? It would be really helpful to
    >> give an example using my  scenario since I have a lot of trouble
    >> understanding other examples on the web because the data is not set
    >> up like my data.
    >> 
    >> Thanks so much!!!
    >> Amanda
    >> 
    >> 
    >> 
    >> 
    >> [[alternative HTML version deleted]]
    >> 
    >> ______________________________________________
    >> 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.
    >> 

    JIV> [[alternative HTML version deleted]]

    JIV> ______________________________________________
    JIV> R-help at r-project.org mailing list
    JIV> https://stat.ethz.ch/mailman/listinfo/r-help
    JIV> PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
    JIV> and provide commented, minimal, self-contained, reproducible code.