On Oct 19, 2013, at 9:28 PM, Taiyun Wei wrote: > Dear All, > >> opt = list() >> opt$aa <<- TRUE > Error in opt$aa <<- TRUE : object 'opt' not found Try _not_ using `<<-` > Why? There wasn't an object by htat name in the enclosing environment. -- David Winsemius Alameda, CA, USA