looping over factors

"Samuelson," == Samuelson, Frank* <Samuelson> writes:

> How does one loop over factors? 

You can loop on the levels of your factor:

b<-factor(c('caseX','caseY', 'caseZ', 'caseX'))
b

[1] caseX caseY caseZ caseX
Levels: caseX caseY caseZ

for ( i in levels(b) ) { print(i) }

[1] "caseX"
[1] "caseY"
[1] "caseZ"

Mike