[R] comparing a vactor of values in IF statement.

[Ravi Varadhan]

Both

V[V > 0.5] <- 1 - V[V > 0.5]

and 

ifelse(V>0.5, 1-V,V)

should do it.

Ravi.

--------------------------------------------------------------------------
Ravi Varadhan, Ph.D.
Assistant Professor,  The Center on Aging and Health
Division of Geriatric Medicine and Gerontology
Johns Hopkins University
Ph: (410) 502-2619
Fax: (410) 614-9625
Email:  rvaradhan at jhmi.edu
--------------------------------------------------------------------------
> -----Original Message-----
> From: r-help-bounces at stat.math.ethz.ch [mailto:r-help-
> bounces at stat.math.ethz.ch] On Behalf Of Jagarlamudi, Choudary
> Sent: Friday, May 20, 2005 1:59 PM
> To: r-help at stat.math.ethz.ch
> Subject: [R] comparing a vactor of values in IF statement.
> 
> Hi,
> 
>  my vector V<- c(1,0.5,0.06,0.056,0.01,0.04,0.4,0.9,0.82,0.1)
> 
>   if( V > 0.5) { V <- 1 - V }
> 
> I get  a warning saying only the first element will be used in comparing
> (if V > 0.5).
> However, my results tell me vis-versa ,it actually compares every element
> of the vector V with 0.5 and that is waht i want it to do.
> Using a for loop is expensive and time consuming since my actual vector is
> 15000 values.
> 
> Any help to rectify the warning i get is appreciated.
> 
> Thank You.
> 
> Choudary Jagarlamudi
> Instructor
> Southwestern Oklahoma State University
> STF 254
> 100 campus Drive
> Weatherford OK 73096
> Tel 580-774-7136
> 
> 	[[alternative HTML version deleted]]
> 
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