try:
Start <- ifelse (DateFirstEven < DateSecondEvent,
(DateFirstEvent+DateSecondEvent)/2, DateFound)
On 7/25/07, James J. Roper <jjroper at gmail.com>
wrote:> Greetings,
>
> I have some confusion with the use of if - else. Let's say I have a
> four variables as follows:
>
> Condition DateFound DateFirstEvent
> DateSecondEvent
> NA 10Jan2000 NA
NA
> 0 05Jan2000 07Jan2000
> 10Jan2000
> 1 07Jan2000 07Jan2000
> 08Jan2000
> 2 09Jan2000 NA
NA
>
> Now, what I need to do is make a new variable that is either the
> midpoint of the first and second event dates, or the date found (I
> will call Start).
>
> I tried an if - else condition as follows:
>
> Start <- if (DateFirstEven < DateSecondEvent)
> (DateFirstEvent+DateSecondEvent)/2 else DateFound
>
> I also tried
>
> Start <- if (any(DateFirstEven < DateSecondEvent))
> (DateFirstEvent+DateSecondEvent)/2 else DateFound
>
> Only the first half of the expression was ever evaluated.
>
> I hope I have not been to brief, and will certainly appreciate any help.
>
> Thanks,
>
> Jim
>
> --
> James J. Roper
> Population Dynamics and Conservation of
> Terrestrial Vertebrates
> Caixa Postal 19034
> 81531-990 Curitiba, Paran?, Brasil
> ======================================> E-mail:
jjroper at gmail.com
> Phone/Fone/Tel?fono: 55 41 33611764
> celular: 55 41 99870543
> Casa: 55 41 33857249
> ======================================> Ecologia e Conserva??o na UFPR
> bio.ufpr.br/ecologia
> ---
> jjroper.googlepages.com
> arsartium.googlepages.com
>
> ______________________________________________
> R-help at stat.math.ethz.ch mailing list
> stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide
R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
>
--
Jim Holtman
Cincinnati, OH
+1 513 646 9390
What is the problem you are trying to solve?