[R] Matrix as input to xyplot {lattice} - proper extended formula syntax

[Bryan Hanson]

Thanks David, your way of constructing df is much more compact than what I
was using, so I've incorporated it.  I also had my rows and columns
transposed relative to how xyplot wanted them (though I had tested for that,
other problems interfered).

In my case, I may have varying numbers of y columns, from y.1 to y.n let's
say.  Is there an easy way of creating the phrase y.1+y.2+...y.n to pass to
xyplot, or even better, some sort of syntax that says "take all y.n" and
plot them against x?

Thanks, Bryan


On 9/6/09 12:51 AM, "David Winsemius" <dwinsemius at comcast.net> wrote:

> I'm not exactly sure what structure df has. Here's my effort to
> duplicate it:
> 
> df <- data.frame(y=matrix(rnorm(24), nrow=6), x=1:6)
>> df
>           y.1        y.2        y.3        y.4 x
> 1  0.1734636  0.2348417 -1.2375648 -1.3246439 1
> 2  1.9551669 -1.1027262 -0.7307332  0.3953752 2
> 3 -0.7645778  1.6297861  0.4743805 -0.4476145 3
> 4 -0.5308756 -0.5246534 -0.3854609 -1.6097777 4
> 5  0.7406525 -0.8691720 -0.8194084  1.6122059 5
> 6 -0.9625619 -1.0774165  1.0760829  0.3659436 6
> 
> And this seems to accomplish the desired task. Presumably you have
> assigned off-stage the value of title to a meaningful character string?
> 
>> p <- xyplot(y.1+y.2+y.3+y.4 ~ x |1:4, data = df, main =
> "title" ,layout=c(1,4) )
>> p
> 
> 
> 
> 
> On Sep 5, 2009, at 11:52 PM, Bryan Hanson wrote:
> 
>> Hello R Folks...
>> 
>> I have a list with the following structure:
>> 
>>> str(df)
>> List of 3
>> $ y    : num [1:4, 1:1242] -0.005379 0.029874 -0.023274 0.000655
>> -0.004537
>> ..
>> $ x    : num [1:1242] 501 503 505 507 509 ...
>> $ names: Factor w/ 4 levels "PC Loading 1",..: 1 2 3 4
>> 
>> I want to plot each row of df$y against df$x, and have each plot in
>> it¹s own
>> panel according to the levels of df$names.  The following works in
>> the sense
>> that the layout is right, but the y values have clearly been
>> recycled or
>> skipped in some fashion (and an error is thrown for each panel that
>> the
>> length of x and y aren¹t the same):
>> 
>> p <- xyplot(y ~ x | names, data = df, main = title,
>>        layout = c(1, dim(y)[1])
>> 
>> In reviewing the extended formula interface in the Lattice Book,
>> what I want
>> to happen is y1 + y2 + y3 + y4 ~ x | names, outer = TRUE
>> 
>> I see two options: figure out a way to create the extended formula
>> on the
>> fly (and the actual number of rows in y may vary), which seems
>> potentially
>> tricky, or create a data frame by stacking each row of y and
>> repeating x and
>> names to match.  This seems like a waste of memory.
>> 
>> I¹ve looked through the archives and haven¹t come across something
>> quite
>> like this, or at least I don¹t recognize it if I have!  Is there a
>> more
>> elegant way to tell xyplot I want to use each row of y repeatedly
>> with the
>> same x, in a loop-like fashion?
>> 
>> TIA.  Bryan
>> *************
>> Bryan Hanson
>> Professor of Chemistry & Biochemistry
>> DePauw University, Greencastle IN USA
>> 
>> 
>> [[alternative HTML version deleted]]
>> 
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> 
> David Winsemius, MD
> Heritage Laboratories
> West Hartford, CT
>