R help - Sep 2009 - How to convert a frame to a matrix while maintaining that a number is still a number?

Hi,

See the code below.

'x' is a frame. x$C1 are all numbers 1, 2 and 3.

'as.matrix(x)' convert x$C1 to strings "1", "2" and
"3". I'm wondering
how to maintain that the first column of 'as.matrix(x)' still numbers.

Regards,
Peng

$ cat read.csv
"C1","C2"
"1","x"
"2","y"
"3","z"
$ Rscript read.csv.R
> x=read.csv("read.csv")
> str(x)
'data.frame':   3 obs. of  2 variables:
 $ C1: int  1 2 3
 $ C2: Factor w/ 3 levels "x","y","z": 1 2
3
> as.matrix(x)
     C1  C2
[1,] "1" "x"
[2,] "2" "y"
[3,] "3" "z"
>

You can't do this using matrix class,

matrix convert all values to same class, in this case, character.

On Wed, Sep 16, 2009 at 7:12 PM, Peng Yu <pengyu.ut at gmail.com>
wrote:
> Hi,
>
> See the code below.
>
> 'x' is a frame. x$C1 are all numbers 1, 2 and 3.
>
> 'as.matrix(x)' convert x$C1 to strings "1", "2"
and "3". I'm wondering
> how to maintain that the first column of 'as.matrix(x)' still
numbers.
>
> Regards,
> Peng
>
> $ cat read.csv
> "C1","C2"
> "1","x"
> "2","y"
> "3","z"
> $ Rscript read.csv.R
>> x=read.csv("read.csv")
>> str(x)
> 'data.frame': ? 3 obs. of ?2 variables:
> ?$ C1: int ?1 2 3
> ?$ C2: Factor w/ 3 levels "x","y","z": 1 2 3
>> as.matrix(x)
> ? ? C1 ?C2
> [1,] "1" "x"
> [2,] "2" "y"
> [3,] "3" "z"
>>
>
> ______________________________________________
> R-help at r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide
http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
>


-- 
Henrique Dallazuanna
Curitiba-Paran?-Brasil
25? 25' 40" S 49? 16' 22" O