That was very clever. Worked perfectly, thanks!
And thanks to everyone else who provided feedback.
On Jun 5, 2010, at 5:46 AM, jim holtman wrote:
> It this what you are looking for:
>
>> set.seed(1)
>> # create range for each possible class
>> # 'name' the values so you can use them in the 'sapply' function
>> lows<-c(a=1, b=2, c=3, d=4, e=5)
>> highs<-c(a=5, b=6, c=7, d=8, e=9)
>>
>> # data values
>> vals<-sample(1:10,100,replace=T)
>>
>> #classes
>> classes<-sample(letters[1:5],100,replace=T)
>>
>> # split the data so that you retain the 'classes' name
>> x.split <- split(vals, classes)
>> percentage <- sapply(names(x.split), function(.class){
> + # compute the percentage based on 'class'
> + sum((x.split[[.class]] >= lows[.class]) &
> + (x.split[[.class]] <= highs[.class])) /
> length(x.split[[.class]]) * 100
> + })
>> percentage
> a b c d e
> 50.00000 45.00000 62.50000 54.54545 55.55556
>>
>
>
> On Fri, Jun 4, 2010 at 4:02 PM, Mark Ebbert <mark.ebb...@hci.utah.edu> wrote:
>> Dear R gurus,
>>
>> I am trying perform what I believe will be a pretty simple task, but I'm
>> struggling to figure out how to do it. I have two vectors of the same
>> length, the first is numeric and the second is factor. I understand that
>> tapply is perfect for applying a function to the numeric vector by subsets
>> of the factors in the second vector. My issue is trying to make use of two
>> other vectors within the custom function I've written for tapply. The two
>> other vectors are a high and low value for each subset I am breaking my data
>> into, and I want to calculate the percentage of data points that fall into
>> each respective range. I will attempt to provide a coherent example:
>>
>> # create range for each possible class
>> lows<-c(1,2,3,4,5)
>> highs<-c(5,6,7,8,9)
>>
>> # data values
>> vals<-sample(1:10,100,replace=T)
>>
>> #classes
>> classes<-sample(letters[1:5],100,replace=T)
>>
>> # Try to calculate percentage of values that fall
>> # into the respective range for the given class.
>> percentages<-tapply(vals,classes,
>> function(i){
>> length(i[i>=lows[index] & i<=highs[index]])/length(i) # I
>> don't know how to actually keep an index count in tapply, but I'm guessing
>> there's a better way.
>> })
>>
>> I really appreciate any help.
>>
>> ME
>> ______________________________________________
>> R-help@r-project.org 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 that you are trying to solve?
______________________________________________
R-help@r-project.org 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.
