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

Dimitris Rizopoulos dimitris.rizopoulos at med.kuleuven.be
Thu Apr 6 16:28:25 CEST 2006

```try the following:

out <- data.matrix(d)
dimnames(out) <- NULL
out

Best,
Dimitris

----
Dimitris Rizopoulos
Ph.D. Student
Biostatistical Centre
School of Public Health
Catholic University of Leuven

Tel: +32/(0)16/336899
Fax: +32/(0)16/337015
Web: http://www.med.kuleuven.be/biostat/
http://www.student.kuleuven.be/~m0390867/dimitris.htm

----- Original Message -----
From: "Muhammad Subianto" <msubianto at gmail.com>
To: <r-help at stat.math.ethz.ch>
Sent: Thursday, April 06, 2006 4:16 PM
Subject: [R] convert a data frame to matrix - changed column name

>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?
>
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