# [R] how to make the matrix as factors

Pierre BADY pierre.bady at univ-lyon1.fr
Sun Dec 19 10:52:00 CET 2004

```Hi,

The argument df of the function 'mcaÂ’ requires only a data.frame (not matrix)
containing only factors.

# Example:
?data.frame

library(MASS)
?mca

# we  construct the matrix.
size <- c(3,2,3,3,3,3,3,3,3)
texture <- c(2,3,2,2,2,2,2,2,2)
leaf <- cbind(size,texture)

new.mca <- mca(leaf)

# Error in mca(leaf) : All variables must be factors

# now, we construct a data.frame.
dleaf <- as.data.frame(leaf)
summary(dleaf)

# we transform each variable into a factor.
dleaf[,2] <- as.factor(dleaf[,2])
dleaf[,1] <- as.factor(dleaf[,1])
summary(dleaf)
new.mca <- mca(dleaf)
new.mca
#

cheers,

P.BADY

En rÃ©ponse Ã  ys03165003 at student.ecnu.edu.cn:

> Hi All,
>
> Thanks for you help, I have loaded the library MASS to call the mca. But
> wen I
> want to do the mca, there is another problem, for example
> --------
> --------
> > leaf <- read.table("C:/Documents and Settings/wxh-c/Ã—Ã€ÃƒÃ¦/1.txt",
> + col.names=c("size","texture"),header=TRUE)
> > leaf
>     size texture
> 1      3       3
> 2      2       2
> 3      3       2
> 4      3       2
> 5      3       2
> 6      3       3
> 7      3       2
> 8      3       2
> 9      3       2
> > attach(leaf)
> > require(MASS)
> Loading required package: MASS
> [1] TRUE
> > new.mca <- mca(leaf)
> Error in mca(leaf) : All variables must be factors
> ---------
> So, what should I do to make the matrix as factor. Waiting for you
> answers.
> Thanks!
>
>                                                                 jeff
>
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---------------------------------------------------------
Pierre BADY     <Â°)))><
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```

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