Without actually running the code, one problem seems to be that the line if(database$year[i]>90) is comparing a character vector to 90 and not the numbers that you are expecting.
You could try this instead: database$year <- as.numeric(database$year) ifelse(database$year > 90, database$year + 1900, database$year + 2000) Jason Law Statistician City of Portland, Bureau of Environmental Services Water Pollution Control Laboratory 6543 N Burlington Avenue Portland, OR 97203 -5452 [EMAIL PROTECTED] -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] Behalf Of Jonas Malmros Sent: Monday, December 17, 2007 4:53 PM To: r-help@r-project.org Subject: [R] Why is conversion not working? I have a data frame, where two last columns - "month" and "year" - are character vectors. The "year" vector is made of two numbers (i.e. "97" for 1997, "07" for 2007, etc) What I want to do is to create a variable "Year" that is mode numeric and where each record is a four-figure number (1997, 2007,...) I have about 40000 rows in the dataframe, the observations are for 10 years (so there are multiple rows for each year). I tried the following, but the program runs and runs, and if I abort it all the years in "Year" are 1997: for(i in 1:dim(database)[1]){ if(database$year[i]>90) { database$Year[i] <- as.numeric(database$year[i])+1900 } else { database$Year[i] <- as.numeric(database$year[i])+2000 } } Thanks in advance for explanations. Regards, JM -- Jonas Malmros Stockholm University Stockholm, Sweden ______________________________________________ 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. ______________________________________________ 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.
