You never create a variable called "Mat2002273" or "Mat2002361" so you
can't ask R to loop over all the values between them.
If I were you, I'd code something like this:
lf <- list.files()
# PUT IN SOME CODE TO REMOVE FILES YOU DON'T WANT TO USE
pv <- vector("numeric", length(lf))
for(i in lf) pv[i] <- mean( read.csv(lf, header = TRUE)[,"Pixelvalues"])
print(pv)
Michael
On Fri, Dec 2, 2011 at 12:15 PM, Komine <moma...@yahoo.fr> wrote:
> Hi,
> I try to build a loop difficultly.
> I have in a folder called Matrices several files (.csv) called Mat2002273,
> Mat2002274 to Mat2002361.
> I want to calculate for each file the mean of the column called Pixelvalues.
> I try this code but as result, I have this message: Mat2002273 not found
>
>>essai<-read.table("C:\\Users\\Desktop\\Matrices\\Mat2002273.csv",sep=";",dec=",",header=TRUE)
>>essai
>>a <- NULL
>>for(i in Mat2002273:Mat2002361){
>>paste(mean(essai$Pixelvalues))
>>a[i] <- paste(mean(essai$Pixelvalues))
>>print(a[i])
>>}
>
> Thank you for your help
>
>
>
>
> --
> View this message in context:
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> Sent from the R help mailing list archive at Nabble.com.
>
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