reshape2's dcast() Adds NAs to Data Frame
On Wed, 8 Aug 2012, Jeff Newmiller wrote:
The explanation is that this is normal and consistent with behavior of factors in general. If you don't want that, it is common to work with character data instead of factors, only converting to factor when needed. In most cases I invoke read.table with the as.is=TRUE argument and delay converting to factors until I need them. Other people convert from factor to character and back to factor to get rid of unwanted factor levels on an as-needed basis.
Jeff, First thing tomorrow I will research the difference between characters and data; I assumed they were the same. Thanks, Rich