Part of that decision may depend upon how big the dataset is and what is intended to be done with the ID's:
> object.size(1011001001001) [1] 36 > object.size("1011001001001") [1] 52 > object.size(factor("1011001001001")) [1] 244 They will by default, as Andy indicates, be read and stored as doubles. They are too large for integers, at least on my system: > .Machine$integer.max [1] 2147483647 Converting to a character might make sense, with only a minimal memory penalty. However, using a factor results in a notable memory penalty, if the attributes of a factor are not needed. If any mathematical operations are to be performed with the ID's then leaving them as doubles makes most sense. Dan, more information on the numerical characteristics of your system can be found by using: .Machine See ?.Machine and ?object.size for more information. HTH, Marc Schwartz On Fri, 2004-08-13 at 21:02, Liaw, Andy wrote: > If I'm not mistaken, numerics are read in as doubles, so that shouldn't be a > problem. However, I'd try using factor or character. > > Andy > > > From: Dan Bolser > > > > I store an id as a big number, could this be a problem? > > > > Should I convert to at string when I use read.table(... > > > > example id's > > > > 1001001001001 > > 1001001001002 > > ... > > 1002001002005 > > > > > > Bigest is probably > > > > 1011001001001 > > > > Ta, > > Dan. > > ______________________________________________ [EMAIL PROTECTED] mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html