[R] Writing do and resample functions

[Ben Ward]

I've just loaded the workspace and done

 > methods('*')
And got the ouptut
[1] *.difftime *.repeater

I'm not entirely sure on what this repeater and as.repeater is. From my 
reading when one want to repeat stuff for say bootstrapping, you have to 
use repeat as part of a function and put in some sort of qualification 
that end the repetitions. Coding functions is a bit beyond what is 
taught on my BSc Biology course. However, I do know that if I do the 
same in a new R session:

 > methods('*')
[1] *.difftime

*.repeater is missing. So to clarify my understanding, the * is the 
problem because it hasn't got this .repeater value attributed to it?

Thanks,
Ben Ward.


On 04/01/2011 12:30, Erich Neuwirth wrote:
> It seems that the textbook workspace you are using as a method
> definition for * for class repeater. Load the workspace and try
> methods(`*`)
> If you get something like '*.repeater' this suspicion is confirmed
>
>
> On 1/4/2011 11:36 AM, Ben Ward wrote:
>> Hi,
>>
>> I'm trying to take a function from a workspace download provided in a
>> stats textbook book, so I have it in my workspace to use all the time.
>>
>> I opened the workspace and typed the names of the two functions to get
>> the code that makes them up:
>> -------------------------------------------------------------------------------------
>>
>>> resample
>> function(d, size, replace=TRUE,prob=NULL,within=NULL) {
>>    if (!is.null(within)) return( resample.within(d,
>> within,replace=replace) )
>>    if (is.null(dim(d))) {
>>       # it's just a vector
>>       if (missing(size)) size=length(d)
>>          return( d[ sample(1:length(d),size, replace=replace, prob=prob)])
>>    }
>>    else {
>>       if (missing(size)) size = dim(d)[1];
>>       inds = sample(1:(dim(d))[1], size, replace=replace, prob=prob)
>>       if (is.data.frame(d) | is.matrix(d)) {
>>          return(d[inds,]);
>>       } else {
>>          return(d[inds]);
>>       }
>>    }
>> }
>> -------------------------------------------------------------------------------------
>>
>>> do
>> function(n=10){
>>    as.repeater(n)
>> }
>> -------------------------------------------------------------------------------------
>>
>>> as.repeater
>> function(n=5){
>>    foo = list(n=n)
>>    class(foo) = 'repeater'
>>    return(foo)
>> }
>>
>> Then I made the functions in my workspace by choosing the name (same
>> name), and then "=" and then copied and pasted the function, beginning
>> with function( and ending with the final }'s.
>>
>> But when I try to do the following in my workspace afterwards:
>>
>> samps = do(500)* coef(lm(MIC.~1+Challenge+Cleaner+Replicate,
>> data=resample(ecoli)))
>> sd(samps)
>>
>> I get an error:
>> Error in do(500) * coef(lm(MIC. ~ 1 + Challenge + Cleaner + Replicate,  :
>> non-numeric argument to binary operator.
>>
>> But in the workspace that comes with that book, I get a decent output:
>>
>> sd(samps)
>>      (Intercept)       Challenge   CleanerGarlic  ReplicateFirst
>> ReplicateFourth
>>        3.9455401       0.7178385       1.6830641       5.4564926
>> 5.4320998
>> ReplicateSecond  ReplicateThird
>>        5.3895562       5.5422622
>>
>> Is there anybody out there who know a lot more about programming
>> functions in R than I do, that might know why this is giving me the
>> error? I don't understand why one workspace would accept the model
>> formula, when the other give me the non-numeric argument to binary
>> vector, the only vector that's not numerical is Replicate, but I don't
>> that's what the error is talking about.
>>
>> Thanks,
>> Ben Ward.
>>
>> ______________________________________________
>> R-help at 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.
>>
>
>