Hello all,
I've run into what I bet is a silly problem; however, I've been
trying to get around it now for a couple weeks and every time I think
I have the answer it still doesn't work. So I apologize in advance
if this is painfully obvious, but I've run out of ideas and would
really appreciate any input.
My situation is this, I'm importing a number of tab delimited text
files that contain chromatogram data that I am trying to display
adjacent to a dendrogram. Since I look at multiple files I import
them as file1, file2, file3, etc. To display them in the order that
comes from the dendrogram I want to use order.dendrogram, which gives
me a vector of numbers that is the order which I want the
chomatograms to be displayed.
Here's the problem: I want to be able to set up a loop in which use
"file" as the base name then concatenate the number that follows
after it as the value at order.dendrogram[i] in a plot function. So
something like:
assume there is a dendrogram called peak.dend
numberOfChromatograms<-20
i<-1
ord<-order.dendrogram(peak.dend)
while(i<=numberOfChromatograms){
plot(file[ord[i])
i<-i+1
}
I know that this particular plot function won't work, but for the
purposes of this assume that it would if I just put in the number as
opposed to ord[i]. But when I try this I get an error that "file"
does not exist.
So I thought that the problem was concatenation. My solution was to
use the paste function:
> ord<-order.dendrogram(peak.dend)
> ord
[1] 13 14 17 18 7 8 1 2 3 4 15 16 5 6 23 24 19 20 9 10 11
12 21 22
> z<-paste("file",ord[1],sep="")
> z
[1] "file13"
But when I try to plot this it won't work. "Ah ha!" I thought, "it's
the quotes."
so I try to unquote it:
> noquote(z)
[1] file13
Yes! But it still won't plot. For some reason the statement file13
is not getting evaluated. If I type in exactly plot(file13) it
works. If I explicitly store file13 in z
> z<-file13
then
> plot(z)
it works.
But if I I do the following:
> z<-noquote(paste("file",13,sep=""))
then
> plot(z)
it will not plot (specifically it tells me that x and y are lengths
differ which tells me that it's not evaluating the result of z, just
inputting it as is).
I've naively tried eval(z), but I get the same result.
So I know this is a stupid problem and as soon as somebody tells me
the answer I'm going to smack my head and say "Duh!", but right now I
don't even know what terms to search for. Thanks in advance for any
help.
-John
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