[R] identify an element in a column

[Dimitris Rizopoulos]

try this:

x <- 1:10
y <- 11:20
z <- cbind(x, y)

ind <- x == 5
z[ind, "y"] <- z[ind, "y"] - 1
z


I hope it helps.

Best,
Dimitris


On 2/22/2011 6:18 PM, Hongwei Dong wrote:
> Hi, R users,
>
> I'm wondering if I can identify an element in a column by an element in
> another column. For example:
>
> x<-1:10
> y<-11:20
> z<-cbind(x,y)
> z
>       x  y
>   [1,]  1 11
>   [2,]  2 12
>   [3,]  3 13
>   [4,]  4 14
>   [5,]  5 15
>   [6,]  6 16
>   [7,]  7 17
>   [8,]  8 18
>   [9,]  9 19
> [10,] 10 20
>
> What I want to do is: when x=5, y=y-1
>
> Anyone can tell me how to do this? Thanks.
>
>
> Gary
>
> 	[[alternative HTML version deleted]]
>
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>

-- 
Dimitris Rizopoulos
Assistant Professor
Department of Biostatistics
Erasmus University Medical Center

Address: PO Box 2040, 3000 CA Rotterdam, the Netherlands
Tel: +31/(0)10/7043478
Fax: +31/(0)10/7043014
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