Hi John,
On Sun, Apr 24, 2011 at 1:10 PM, Sparks, John James <jspa...@uic.edu> wrote:
> Dear R Helpers,
>
> I have another one of those problems involving a very simple step, but due
> to my inexperience I can't find a way to solve it. I had a look at a
> number of on-line references, but they don't speak to this problem.
>
> I have a variable with 20 values
>
>> table (testY2$redgroups)
>
> 1 2 3 4 5 6 7 8 9 10 11 12
> 13 14 15 16 17 18 19 20
> 69 734 6079 18578 13693 6412 3548 1646 659 323 129 88
> 90 40 57 33 36 17 6 13
>
> Values 18,19 and 20 have small counts. So, I want to set the value of
> redgroups for these rows to 17 in order to combine groups. I would think
> that it would be as easy as
>
> if(testY2$redgroups>17) testY2$redgroups<-17
"if" is not vectorized, it is designed for using in things like logic
trees (e.g., if (na.rm) {remove-missing-values} else ....). You are
looking for ifelse (see ?ifelse for documentation). Something like:
testY2$redgroups <- with(testY2, ifelse(redgroups > 17, 17, redgroups))
HTH,
Josh
>
> following the syntax that I have seen in the manuals. However, I get the
> error message
>
> Warning message:
> In if (testY2$redgroups > 17) testY2$redgroups <- 17 :
> the condition has length > 1 and only the first element will be used
>
> Can someone please tell me the correct syntax for this? I would really
> appreciate it.
>
> Appreciatively yours,
> --John J. Sparks, Ph.D.
>
> ______________________________________________
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> PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
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>
--
Joshua Wiley
Ph.D. Student, Health Psychology
University of California, Los Angeles
http://www.joshuawiley.com/
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