[R] newbie question about index

[Petr Pikal]

Hallo

probably there are other options but

outer(1:3,a, "==")*1

can do what you want.

HTH
Petr



On 31 Aug 2006 at 22:41, z s wrote:

Date sent:      	Thu, 31 Aug 2006 22:41:27 +0800 (CST)
From:           	z s <flyhyena at yahoo.com.cn>
To:             	r-help at stat.math.ethz.ch
Subject:        	[R] newbie question about index

> Hi,
> 
>   I am trying to convert a variable a = sample(1:3,100,rep = T)
>   represents choices into a 3X100 dummy varible b with corresponding
>   element set to 1 otherwise 0.
> eg.
> 
> a: 1 3 2 1 2 3 1 1....
> 
> b: 1 0 0 1 0 0 1 1..
>     0 0 1 0 1 0 0 0...
>     0 1 0 0 0 1 0 0...
> 
>  Is there something like b[a] =1 existing? I could not figure this out
>  myself.
> 
> 
> ---------------------------------
>  Mp3˙čżńËŃ-иčČȸč¸ßËŮĎ   
>  [[alternative HTML version deleted]]
> 
> 

Petr Pikal
petr.pikal at precheza.cz