[R] element wise conditional assignment in r

[Phil Spector]

John -
    Is this what you're looking for?

> r = sample(c(0,1),10,replace=TRUE)
> r
  [1] 0 1 0 1 1 0 0 1 0 1
> v = 1:10
> ifelse(r == 1,v-1,v)
  [1] 1 1 3 3 4 6 7 7 9 9


 					- Phil Spector
 					 Statistical Computing Facility
 					 Department of Statistics
 					 UC Berkeley
 					 spector at stat.berkeley.edu





On Fri, 1 Oct 2010, yunjiangster wrote:

>
> Hi,
>  I am looking for a one-liner code for the following situation
> say I have a vector r of 0 and 1's, and another vector v of equal length. I
> want to assign v[i]-1 to v[i] if r[i]=1, for all i. How would I do that
> using mapply or any other batch processing keywords? thanks.
>
>  John
> -- 
> View this message in context: http://r.789695.n4.nabble.com/element-wise-conditional-assignment-in-r-tp2951963p2951963.html
> Sent from the R help mailing list archive at Nabble.com.
>
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