[R] how to skip part of the code

[Robert Baer]

On 3/20/2013 8:21 AM, PIKAL Petr wrote:
> Hi
>
>> -----Original Message-----
>> From: r-help-bounces at r-project.org [mailto:r-help-bounces at r-
>> project.org] On Behalf Of Andras Farkas
>> Sent: Wednesday, March 20, 2013 2:11 PM
>> To: r-help at r-project.org
>> Subject: [R] how to skip part of the code
>>
>> Dear All,
>>
>> another quick question, this one is on skipping part of my code, so let
>> us say:
>>
>> a <-5
>> b <-2
>> e <-0
>>
>> d <-a+b
>> f <-a-b
>>
>> what I would like to do is to have R NOT to calculate the value for d
>> in case the value of e equals to zero (essentially skip that "chunk"),
>> but instead move on to calculate te value for f. In the code I am
>> working with the value of e changes, and I would like to calculate d
>> and f at all times when the value of e is greater then zero. If
>> possible, I would like to do this without using the functions "ifelse"
>> and "if else"
> Why? This is exactly the reason for which if else was invented?
>
> I am not sure if some simple solution without if is available.
>
> if (e > 0) { d <- a+b; f <- a-b }
>
> seems to be simple.
>
> Regards
> Petr
I second Petr on the question, why not use if?  But this might meet your 
criteria.
a <- 5
b <- 2
e <- 0

#
dat <- data.frame(a, b, e)


dat$d[dat$e  > 0] <- a + b
dat$f <- a - b



>> appreciate the help,
>>
>> Andras
>> 	[[alternative HTML version deleted]]
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-- 

Robert W. Baer, Ph.D.
Professor of Physiology
Kirksille College of Osteopathic Medicine
A. T. Still University of Health Sciences
Kirksville, MO 63501 USA