[R] Repeat a loop until...

["Dénes TÓTH"]

If you want to generate truncated distributions, package 'tmvtnorm' can
help you out.

Regards,
  Denes



>>
>> Dear all,
>>
>> I know there have been various questions posted over the years about
> loops
>> but I'm afraid that I'm still stuck.  I am using Windows XP and R 2.9.2.
>> I am generating some data using the multivariate normal distribution
>> (within the 'mnormt' package). [The numerical values of sanad and covmat
>
>> are not important.]
>> > datamat <- rmnorm(n=1500,mean=c(mean(sanad[,1]),mean(sanad[,2]),mean
>> (sanad[,3])),varcov=covmat)
>>
>> The middle column of 'datamat' is simulated data for age.  Obviously
> some
>> of the simulated values are not going to be sensible.  Therefore I'd
> like
>> to set up a function that looks at each row of 'datamat' and if the
> value
>> for the middle column is <5 or >86 then the whole row is replaced by
>> another imputed row.  Of course, the problem is that the imputed value
> for
>> age may be outside my acceptable range too.
>>
>> If there a way to set up a loop such that it keeps checking each row
> until
>> the values are within the range?
>>
>> So far I have the following but this doesn't repeat the process.
>> ctstrunk <- function(data)
>>                 {
>>                 for(i in 1:nrow(data)){
>>                 if(data[i,2]<5)
>>                 data[i,]<-rmnorm(n=1,mean=c(mean(sanad[,1]),mean(sanad[,
>> 2]),mean(sanad[,3])),varcov=covmat)
>>                 if(data[i,2]>86)
>>                 data[i,]<-rmnorm(n=1,mean=c(mean(sanad[,1]),mean(sanad[,
>> 2]),mean(sanad[,3])),varcov=covmat)
>>                 }
>>                 return(data)
>>                 }
>>
>> I thought of perhaps a repeat loop such as the following but this loop
>> never stops...
>> ctstrunk <- function(data)
>>                 {
>>                 repeat{
>> for(i in 1:nrow(data)){
>>                 if(data[i,2]<5)
>>                 data[i,]<-rmnorm(n=1,mean=c(mean(sanad[,1]),mean(sanad[,
>> 2]),mean(sanad[,3])),varcov=covmat)
>>                 if(data[i,2]>5){break}
>>                 }
>>                 repeat{
>> for(i in 1:nrow(data)){
>>                 if(data[i,2]>86)
>>                 data[i,]<-rmnorm(n=1,mean=c(mean(sanad[,1]),mean(sanad[,
>> 2]),mean(sanad[,3])),varcov=covmat)
>>                 if(data[i,2]<86){break}
>>                 }
>>                 return(data)
>>                 }
>>
>> I have also tried a while loop but again, the function didn't stop
>> ctstrunk <- function(data)
>>                 {
>>                 for(i in 1:nrow(data)){
>>                 while(data[i,2]<5)
> data[i,]<-rmnorm(n=1,mean=c(mean(sanad
>> [,1]),mean(sanad[,2]),mean(sanad[,3])),varcov=covmat)
>>                 while(data[i,2]>86)
> data[i,]<-rmnorm(n=1,mean=c(mean(sanad
>> [,1]),mean(sanad[,2]),mean(sanad[,3])),varcov=covmat)
>>                 }
>>                 return(data)
>>                 }
>>
>> Many thanks for any assistance you can offer.
>>
>> Kind regards,
>> Laura
>>
>> Laura Bonnett
>> Research Assistant
>> Department of Biostatistics
>> University of Liverpool
>>
>> Telephone: 0151 7944059
>> Email: L.J.Bonnett at liv.ac.uk
>>
>>
>>    [[alternative HTML version deleted]]
>>
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>
> ______________________________________________
> 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.
>