[R] change codes into loops

[David Winsemius]

On Jan 18, 2010, at 7:58 PM, David Winsemius wrote:

>
> On Jan 18, 2010, at 7:19 PM, rusers.sh wrote:
>
>> Hi,
>> See example.
>>  for (i in 1:2) {
>> for (j in 1:3) {
>>    b_1[i,j]<-rank(c(a1[i,j],a2[i,j],a3[i,j]))[1]
>>   b_2[i,j]<-rank(c(a1[i,j],a2[i,j],a3[i,j]))[2]
>>    b_3[i,j]<-rank(c(a1[i,j],a2[i,j],a3[i,j]))[3]
>> }
>> }
>> The inner codes is really repeated, so i want to change the inner  
>> codes
>> into loops. Take nn is from 1 to 3,
>> something like,
>>
>> Anybody can tell me the correct method to specify the above codes?
>
> There is no correct method.

I take that back.

> You cannot index on the object name b_nn that way. R has not been  
> developing using a syntax with that much flexibility.  If you want a  
> 3D array of values, then you could create b_ijn[i, j, nn] and make  
> assignments to it.

You could make  a list of matrices:

for (nn in 1:3) {
     bn[[nn]] <- b[i,j] <- rank(c(a1[i,j]:a3[i,j]))[nn]
# assuming that your right hand construction is meaningful,,,,  
impossible to tell without an example.
}

> But if you tried to do this with paste and assign, you will spending  
> considerably more time degbugging it than it is worth and it would  
> likely be more inefficient than what you have.
>
> -- 
> David.
>
>> Thanks.
>>
>> -- 
>> -----------------
>> Jane Chang
>> Queen's
>>
>> 	[[alternative HTML version deleted]]
>>
>> ______________________________________________
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>> 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.
>
> David Winsemius, MD
> Heritage Laboratories
> West Hartford, CT
>
> ______________________________________________
> 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.

David Winsemius, MD
Heritage Laboratories
West Hartford, CT