On Jul 6, 2009, at 3:16 PM, spime wrote:

>

> Dear R-users,

>

> Recently, I am facing some problems when converting mlbench data

> into matrix

> format.

>

> library(mlbench)

> data(BostonHousing)

> X<- BostonHousing[,1:13]

If you look at X with str(), you will see it has a factor variable.

> y<-BostonHousing[,14]

>

> I want to convert X and y into matrix form. I am getting these obvious

> errors...

>

>> t(X)%*%y

> Error in t(X) %*% y : requires numeric/complex matrix/vector arguments

And since one of the variables was a factor, the result of t(X) (and

of as.matrix(X) for that matter ) becomes a character matrix. Perhaps

data.matrix(X) will serve better?

t(data.matrix(X))%*%y

[,1]

crim 25687.104

zn 168607.800

indus 111564.080

chas 12397.000

nox 6094.428

rm 73924.078

age 732581.140

dis 45713.874

rad 93445.100

tax 4287797.600

ptratio 205316.730

b 4208049.505

lstat 119799.159

>> t(as.matrix(X))%*%(as.matrix(y))

> Error in t(as.matrix(X)) %*% (as.matrix(y)) :

> requires numeric/complex matrix/vector arguments

>

> any kind of suggestions will be very helpful.

> Thanks.

> --

David Winsemius, MD

Heritage Laboratories

West Hartford, CT

______________________________________________

[hidden email] mailing list

https://stat.ethz.ch/mailman/listinfo/r-helpPLEASE do read the posting guide

http://www.R-project.org/posting-guide.htmland provide commented, minimal, self-contained, reproducible code.