R help - Jul 2007 - if - else

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
http://www.bio.ufpr.br/ecologia/
---
http://jjroper.googlepages.com/
http://arsartium.googlepages.com/

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
> http://www.bio.ufpr.br/ecologia/
> ---
> http://jjroper.googlepages.com/
> http://arsartium.googlepages.com/
>
> ______________________________________________
> R-help at stat.math.ethz.ch mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide
http://www.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?