[R] newbie question about index

[Jacques VESLOT]

(a==1)*1
or ifelse(a == 1, 1, 0)
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Jacques VESLOT

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z s a écrit :
> 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.
> 
>  		
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> 
> 
> 
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