3 messages · Charles H. Franklin, John Fox, Uwe Ligges
What is a simple way to convert a factor into a matrix of dummy variables? fm<-lm(y~f) where f is a factor takes care of this in the estimation. I'd like to save the result of expanding f into a matrix for later use. Thanks. Charles
Charles H. Franklin Professor, Political Science University of Wisconsin, Madison franklin at polisci.wisc.edu chfrankl at wisc.edu 608-263-2022 (voice) 608-265-2663 (fax)
Dear Charles, Try model.matrix(~f)[,-1]. Regards, John -------------------------------- John Fox Department of Sociology McMaster University Hamilton, Ontario Canada L8S 4M4 905-525-9140x23604 http://socserv.mcmaster.ca/jfox --------------------------------
-----Original Message----- From: r-help-bounces at stat.math.ethz.ch [mailto:r-help-bounces at stat.math.ethz.ch] On Behalf Of Charles H. Franklin Sent: Tuesday, December 06, 2005 3:03 PM To: r-help at stat.math.ethz.ch Subject: [R] Matrix of dummy variables from a factor What is a simple way to convert a factor into a matrix of dummy variables? fm<-lm(y~f) where f is a factor takes care of this in the estimation. I'd like to save the result of expanding f into a matrix for later use. Thanks. Charles -- Charles H. Franklin Professor, Political Science University of Wisconsin, Madison franklin at polisci.wisc.edu chfrankl at wisc.edu 608-263-2022 (voice) 608-265-2663 (fax)
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What is a simple way to convert a factor into a matrix of dummy variables? fm<-lm(y~f)
model.matrix(y~f) Uwe Ligges
where f is a factor takes care of this in the estimation. I'd like to save the result of expanding f into a matrix for later use. Thanks. Charles