# [R] convert a data frame to matrix - changed column name

Thu Apr 6 16:33:53 CEST 2006

```On this day 06/04/2006 16:22, Robin Hankin wrote:
> Hi
>
> set the column names to NULL:
>
>
> > a <- data.frame(x=1:4,y=4:1)
> > aa <- as.matrix(a)
> > colnames(aa) <- NULL
> > aa

On this day 06/04/2006 16:28, Dimitris Rizopoulos wrote:
> try the following:
>
> out <- data.matrix(d)
> dimnames(out) <- NULL
> out

Thank you very much for your help.

On 4/6/06, Muhammad Subianto <msubianto at gmail.com> wrote:
> I have a question, which very easy to solve, but I can't find a solution.
> I want to convert a data frame to matrix. Here my toy example:
>
> > L3 <- c(1:3)
> > L10 <- c(1:6)
> > d <- data.frame(cbind(x=c(10,20), y=L10), fac=sample(L3, + 6, repl=TRUE))
> > d
>    x y fac
> 1 10 1   1
> 2 20 2   1
> 3 10 3   1
> 4 20 4   3
> 5 10 5   2
> 6 20 6   2
> > is.data.frame(d)
> [1] TRUE
> > sapply(d, function(x) unlist(x, use.names=FALSE))
>       x y fac
> [1,] 10 1   1
> [2,] 20 2   1
> [3,] 10 3   1
> [4,] 20 4   3
> [5,] 10 5   2
> [6,] 20 6   2
> > is.matrix(sapply(d, function(x) unlist(x, use.names=FALSE)))
> [1] TRUE
> >
>
> Yes, I get a matrix TRUE. But I need to change a column name like [,1]
> [,2] [,3]. I need the result like
>
>      [,1] [,2] [,3]
> [1,]   10    1    1
> [2,]   20    2    1
> [3,]   10    3    1
> [4,]   20    4    3
> [5,]   10    5    2
> [6,]   20    6    2
>
> How can I do that?