Your problem is with scoping, not the conversion per se: > > attach(ngrad) > > is.factor(STNW) > [1] FALSE
At this moment, STNW is the same as ngrad$STNW > > ngrad$STNW<-factor(STNW) ## doesn't work Yes it does work, try looking at is.factor(ngrad$STNW) > > is.factor(STNW) > [1] FALSE After you assign to ngrad$STNW, it is no longer the same thing as the attached STNW. You would need to detach and re-attach ngrad for this to be so. There's no automatic synchronisation between the attached STNW and ngrad$STNW; changing one will not change the other. My advice is: never use attach() if you can help it. It's an accident waiting to happen. Get used to typing dataFrame$varname instead of just varname - that way you will always get what you expect. Or use with() instead of attach() in almost every case. HTH Simon Fear Senior Statistician Syne qua non Ltd Tel: +44 (0) 1379 644449 Fax: +44 (0) 1379 644445 email: [EMAIL PROTECTED] web: http://www.synequanon.com Number of attachments included with this message: 0 This message (and any associated files) is confidential and\...{{dropped}} ______________________________________________ [EMAIL PROTECTED] mailing list https://www.stat.math.ethz.ch/mailman/listinfo/r-help
