[R] Combining all possible values of variables into a new...

[jim holtman]

yet another way (as it always is in R):

> x<-c(1,0,0,1,0,0,1,0,0,1)
> y<-c(1,3,2,3,2,1,2,3,2,3)
> z<-c(1,2,1,2,1,2,1,2,1,2)
> d<-as.data.frame(cbind(x,y,z))
> d$myvar <- x*6 + (y-1)*2 + z
>
> d
   x y z myvar
1  1 1 1     7
2  0 3 2     6
3  0 2 1     3
4  1 3 2    12
5  0 2 1     3
6  0 1 2     2
7  1 2 1     9
8  0 3 2     6
9  0 2 1     3
10 1 3 2    12


On Mon, Oct 20, 2008 at 10:10 AM,  <stefan.petersson at inizio.se> wrote:
>
> I'm trying to create a new column in my data.frame where subjects are categorized depending on values on four other columns. In any other case I would just nest a few ifelse statements, however, in this case i have 4*6*2*3=144 combinations and i get weird 'context overflow' errors. So I wonder if there is a more efficient way of doing this.
>
> For illustrational purposes, let's say i have:
>
> x<-c(1,0,0,1,0,0,1,0,0,1)
> y<-c(1,3,2,3,2,1,2,3,2,3)
> z<-c(1,2,1,2,1,2,1,2,1,2)
> d<-as.data.frame(cbind(x,y,z))
>
> and i do:
>
> d$myvar <- ifelse(d$x == 0 & d$y==1 & d$z==1 , d$myvar <- 1,
> ifelse(d$x == 0 & d$y==1 & d$z==2 , d$myvar <- 2,
> ifelse(d$x == 0 & d$y==2 & d$z==1 , d$myvar <- 3,
> ifelse(d$x == 0 & d$y==2 & d$z==2 , d$myvar <- 4,
> ifelse(d$x == 0 & d$y==3 & d$z==1 , d$myvar <- 5,
> ifelse(d$x == 0 & d$y==3 & d$z==2 , d$myvar <- 6,
> ifelse(d$x == 1 & d$y==1 & d$z==1 , d$myvar <- 7,
> ifelse(d$x == 1 & d$y==1 & d$z==2 , d$myvar <- 8,
> ifelse(d$x == 1 & d$y==2 & d$z==1 , d$myvar <- 9,
> ifelse(d$x == 1 & d$y==2 & d$z==2 , d$myvar <- 10,
> ifelse(d$x == 1 & d$y==3 & d$z==1 , d$myvar <- 11,
> ifelse(d$x == 1 & d$y==3 & d$z==2 , d$myvar <- 12, NA))))))))))))
>
> Suggestions?
>
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>



-- 
Jim Holtman
Cincinnati, OH
+1 513 646 9390

What is the problem that you are trying to solve?