R help - Oct 2005 - numeric index of a matrix column name ?

Dear All,

I have written the following small code in order to return
the numeric index of a given matrix column ascii name.
It works, but there is perhaps/probably a predefined function
which does that ?
If yes, thanks for pointing me to it.

# input  : a matrix M and a column ascii name
# output : the numeric index of the column
colnameindex = function(M , colname0)
{
colsnames = names(M[1,]);
theindex  = which(colsnames==colname0);
return(theindex);
}

Thanks
Vincent

probably you need

match(colname0, colnames(M))


I hope it helps.

Best,
Dimitris

----
Dimitris Rizopoulos
Ph.D. Student
Biostatistical Centre
School of Public Health
Catholic University of Leuven

Address: Kapucijnenvoer 35, Leuven, Belgium
Tel: +32/(0)16/336899
Fax: +32/(0)16/337015
Web: http://www.med.kuleuven.be/biostat/
     http://www.student.kuleuven.be/~m0390867/dimitris.htm



----- Original Message ----- 
From: <vincent at 7d4.com>
To: <r-help at stat.math.ethz.ch>
Sent: Friday, October 28, 2005 4:50 PM
Subject: [R] numeric index of a matrix column name ?

> Dear All,
>
> I have written the following small code in order to return
> the numeric index of a given matrix column ascii name.
> It works, but there is perhaps/probably a predefined function
> which does that ?
> If yes, thanks for pointing me to it.
>
> # input  : a matrix M and a column ascii name
> # output : the numeric index of the column
> colnameindex = function(M , colname0)
> {
> colsnames = names(M[1,]);
> theindex  = which(colsnames==colname0);
> return(theindex);
> }
>
> Thanks
> Vincent
>
> ______________________________________________
> R-help at stat.math.ethz.ch mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide! 
> http://www.R-project.org/posting-guide.html
> 

Disclaimer: http://www.kuleuven.be/cwis/email_disclaimer.htm

Dimitris Rizopoulos a ??crit :
> probably you need
> match(colname0, colnames(M))
> I hope it helps.
> Best,
> Dimitris
yes. (why do simple ...)
Thanks Dimitris.
Have a good we.
Vincent