Since you can index a matrix or dataframe with a matrix of logicals, you can use is.na() to index all the NA locations and replace them all with 0 in one command.
> mydata.df <- as.data.frame(matrix(sample(c(as.numeric(NA), 1), size = 30, > replace = TRUE), nrow = 6)) > mydata.df V1 V2 V3 V4 V5 1 1 NA 1 1 1 2 1 NA NA NA 1 3 NA NA 1 NA NA 4 NA NA NA NA 1 5 NA 1 NA NA 1 6 1 NA NA 1 1 > is.na(mydata.df) V1 V2 V3 V4 V5 1 FALSE TRUE FALSE FALSE FALSE 2 FALSE TRUE TRUE TRUE FALSE 3 TRUE TRUE FALSE TRUE TRUE 4 TRUE TRUE TRUE TRUE FALSE 5 TRUE FALSE TRUE TRUE FALSE 6 FALSE TRUE TRUE FALSE FALSE > mydata.df[is.na(mydata.df)] <- 0 > mydata.df V1 V2 V3 V4 V5 1 1 0 1 1 1 2 1 0 0 0 1 3 0 0 1 0 0 4 0 0 0 0 1 5 0 1 0 0 1 6 1 0 0 1 1 > Steven McKinney Statistician Molecular Oncology and Breast Cancer Program British Columbia Cancer Research Centre email: [EMAIL PROTECTED] tel: 604-675-8000 x7561 BCCRC Molecular Oncology 675 West 10th Ave, Floor 4 Vancouver B.C. V5Z 1L3 Canada -----Original Message----- From: [EMAIL PROTECTED] on behalf of David L. Van Brunt, Ph.D. Sent: Wed 3/14/2007 5:22 PM To: R-Help List Subject: [R] replacing all NA's in a dataframe with zeros... I've seen how to replace the NA's in a single column with a data frame *> mydata$ncigs[is.na(mydata$ncigs)]<-0 *But this is just one column... I have thousands of columns (!) that I need to do this, and I can't figure out a way, outside of the dreaded loop, do replace all NA's in an entire data frame (all vars) without naming each var separately. Yikes. I'm racking my brain on this, seems like I must be staring at the obvious, but it eludes me. Searches have come up CLOSE, but not quite what I need.. Any pointers? -- --------------------------------------- David L. Van Brunt, Ph.D. mailto:[EMAIL PROTECTED] "If Tyranny and Oppression come to this land, it will be in the guise of fighting a foreign enemy." --James Madison [[alternative HTML version deleted]] ______________________________________________ R-help@stat.math.ethz.ch 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. ______________________________________________ R-help@stat.math.ethz.ch 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.