[R] Create matrix with column names wiht the same prefix xxxx and that end in 1, 2

[Sorkin, John]

Jeff,
Thank you for your reply.
I should have said with dim names not column names. I want the Mateix to have dim names, no row names, dim names j, k, xxx1, xxx2.

John

John David Sorkin M.D., Ph.D.
Professor of Medicine
Chief, Biostatistics and Informatics
University of Maryland School of Medicine Division of Gerontology and Geriatric Medicine
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On Jul 3, 2023, at 2:11 PM, Jeff Newmiller <jdnewmil using dcn.davis.ca.us> wrote:

?colnames

On July 3, 2023 11:00:32 AM PDT, "Sorkin, John" <jsorkin using som.umaryland.edu> wrote:
I am trying to create an array, myvalues, having 2 rows and 4 columns, where the column names are j,k,xxx1,xxx2. The code below fails, with the following error, "Error in dimnames(myvalues) <- list(NULL, zzz) :
length of 'dimnames' [2] not equal to array extent"

Please help me get the code to work.

Thank you,
John

# create variable names xxx1 and xxx2.
string=""
for (j in 1:2){
name <- paste("xxx",j,sep="")
string <- paste(string,name)
print(string)
}
# Creation of xxx1 and xxx2 works
string

# Create matrix
myvalues <- matrix(nrow=2,ncol=4)
head(myvalues,1)
# Add "j" and "k" to the string of column names
zzz <- paste("j","k",string)
zzz
# assign column names, j, k, xxx1, xxx2 to the matrix
# create column names, j, k, xxx1, xxx2.
dimnames(myvalues)<-list(NULL,zzz)


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