First of all I thank all the friends. Though I have written zero to replace NA in previous email, I will replace with extreme value (99999).
On Tuesday, 21 January 2014 7:05 AM, jwd [via R] <ml-node+s789695n4683894...@n4.nabble.com> wrote: On Sun, 19 Jan 2014 11:39:43 -0800 (PST) kingsly <[hidden email]> wrote: ________________________________ The age variable is being read in as a factor because of the "".  If you were to replace it with NA, the type becomes numerical: Before replacement: str(Elder1) 'data.frame':  5 obs. of  2 variables:  $ ID : Factor w/ 5 levels "ID1","ID2","ID3",..: 1 2 3 4 5  $ age: Factor w/ 3 levels "","35","38": 3 2 1 NA NA Notice that the "" is treated as a factor level. After: str(Elder1) 'data.frame':  5 obs. of  2 variables:  $ ID : Factor w/ 5 levels "ID1","ID2","ID3",..: 1 2 3 4 5  $ age: num  38 35 NA NA NA SO, the question, is what do you want to do with that column?  An "NA" value tells you honestly that the information is missing.  Replacing it with a zero can be misleading and can bias some basic parameter estimates. After you know how you want to treat the data in that field, you may have a better idea of how to handle the missing data. JWD ______________________________________________ [hidden email] mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code. ________________________________ If you reply to this email, your message will be added to the discussion below: http://r.789695.n4.nabble.com/how-to-replace-NA-values-tp4683831p4683894.html To start a new topic under R help, email ml-node+s789695n78969...@n4.nabble.com To unsubscribe from R help, click here. NAML -- View this message in context: http://r.789695.n4.nabble.com/how-to-replace-NA-values-tp4683831p4683896.html Sent from the R help mailing list archive at Nabble.com. [[alternative HTML version deleted]]
______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
