It's because read.table returns a data frame, not a matrix. You can coerce to a
matrix with as.matrix() but you might loose information if your variables are
of different classes.
Michael
On Aug 27, 2012, at 7:07 PM, Cheryl Johnson <johnson.cheryl...@gmail.com> wrote:
> Greetings,
>
> When I try to use the write.table command to save a matrix as a file and
> then open the file with read.table, if I try to take the mean of the entire
> matrix, instead each column of the matrix has its mean calculated. I have
> copied and pasted an example of my code below. When I try to make the
> header false with the read.table command, I am given an error message. I
> would appreciate any guidance for how to average the entire matrix instead
> of just the columns.
>
> Thanks
>
> z=matrix(1:20,4,5)
> write.table(z, file="exercise.csv",sep=",",col.names=NA,qmethod="double")
> j=read.table("exercise.csv",header=T,sep=",",row.names=1)
> mean(j)
>
> V1 V2 V3 V4 V5
> 2.5 6.5 10.5 14.5 18.5
> Warning message:
> mean(<data.frame>) is deprecated.
> Use colMeans() or sapply(*, mean) instead.
>
> [[alternative HTML version deleted]]
>
> ______________________________________________
> R-help@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.
______________________________________________
R-help@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.
