R help - Jul 2023 - Create matrix with column names wiht the same prefix xxxx and that end in 1, 2

?colnames

On July 3, 2023 11:00:32 AM PDT, "Sorkin, John" <jsorkin at
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)
>
>
>______________________________________________
>R-help at r-project.org mailing list -- To UNSUBSCRIBE and more, see
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>PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
>and provide commented, minimal, self-contained, reproducible code.
-- 
Sent from my phone. Please excuse my brevity.

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
Baltimore VA Medical Center
10 North Greene Street<x-apple-data-detectors://12>
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to faxing)

On Jul 3, 2023, at 2:11 PM, Jeff Newmiller <jdnewmil at dcn.davis.ca.us>
wrote:

??colnames

On July 3, 2023 11:00:32 AM PDT, "Sorkin, John" <jsorkin at
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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--
Sent from my phone. Please excuse my brevity.

______________________________________________
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PLEASE do read the posting guide
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and provide commented, minimal, self-contained, reproducible code.

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