R help - Sep 2007 - Plotting (vector,matrix)

Hi all,

I'm still a bit new to R and I'm trying to figure something out.  I have
the solution but the solution is what a C programmer would do :-) and I 
was wondering if someone could tell me the R way of doing it...

What I have is a vector x of length |x|.  And a matrix y of size m rows 
and n columns where n = |x|.  I want to plot m * n points on a graph so 
that the x-coordinates are from x and the y coordinates are from y.

I can plot x with the mean of each column of y as:  plot (x,mean(y)).  
But, to do what I want,  I had to write this pair of for loops:

for (i in 1:dim(y)[1]) {
  for (j in 1:length(x)) {
    points(x[j],y[i,j])
  }
}

to add the points.  I think there must be a better way using some 
variant of apply or matlines.  Even after reading the docs, I'm still 
scratching my head a bit...  Or maybe I copy x out so that it is of size 
m by n?!?  Any thoughts on what an R user would do here?  Thanks!

Ray

matplot(x,y)

On 9/16/07, Raymond Wan <rwan at kuicr.kyoto-u.ac.jp>
wrote:
>
> Hi all,
>
> I'm still a bit new to R and I'm trying to figure something out.  I
have
> the solution but the solution is what a C programmer would do :-) and I
> was wondering if someone could tell me the R way of doing it...
>
> What I have is a vector x of length |x|.  And a matrix y of size m rows
> and n columns where n = |x|.  I want to plot m * n points on a graph so
> that the x-coordinates are from x and the y coordinates are from y.
>
> I can plot x with the mean of each column of y as:  plot (x,mean(y)).
> But, to do what I want,  I had to write this pair of for loops:
>
> for (i in 1:dim(y)[1]) {
>  for (j in 1:length(x)) {
>    points(x[j],y[i,j])
>  }
> }
>
> to add the points.  I think there must be a better way using some
> variant of apply or matlines.  Even after reading the docs, I'm still
> scratching my head a bit...  Or maybe I copy x out so that it is of size
> m by n?!?  Any thoughts on what an R user would do here?  Thanks!
>
> Ray
>
> ______________________________________________
> R-help at r-project.org mailing list
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> PLEASE do read the posting guide
http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
>

-- 
Jim Holtman
Cincinnati, OH
+1 513 646 9390

What is the problem you are trying to solve?

jim holtman wrote:
> matplot(x,y)
>
>   
Ah, thanks -- I got it working!  Actually, I was getting a "must have 
the same number of rows" error since x has the same number of columns as 
y, but x itself is a single row.  This worked for me when I transposed 
y...which is ok for my problem:

matplot(x,t(y))

Thanks!

Ray