Hello Greg, Thanks very much!
This helps! Cheers, Rebecca From: Greg Snow [mailto:538...@gmail.com] Sent: Friday, January 18, 2013 5:17 PM To: Yuan, Rebecca Cc: R help Subject: Re: [R] A smart way to use "$" in data frame The important thing to understand is that $ is a shortcut for [[ and you are moving into the realm where a shortcut is the longest distance between 2 points (see fortune(312)). So your code can be something like: state <- 'oldstate' balance <- 'oldbalance' dataa[[balance]][ dataa[[state]]=='AR' ] You may also benefit from learning to use tools like "with" and "subset" (though subset has its own complications when used inside of other functions) or "grep" and "match" to find the columns of interest. On Fri, Jan 18, 2013 at 12:40 PM, Yuan, Rebecca <rebecca.y...@bankofamerica.com<mailto:rebecca.y...@bankofamerica.com>> wrote: Hello all, I have a data frame dataa: newdate newstate newid newbalance newaccounts 1 31DEC2001 AR 1 1170 61 2 31DEC2001 VA 2 4565 54 3 31DEC2001 WA 3 2726 35 4 31DEC2001 AR 3 2700 35 The following gives me the balance of state AR: dataa$newbalance[data$newstate == 'AR'] 1170 2700 Now, I have another different data frame datab, it is very similar to data, except that the name of the columns are different, and the order of the columns are different: oldstate olddate oldbalance oldid oldaccounts 1 AR 31DEC2012 1234 7 40 2 WA 31DEC2012 2222 3 30 3 VA 31DEC2012 2345 5 23 3 AR 31DEC2012 5673 5 23 datab$oldbalance[datab$oldstate== 'AR' ] 1234 5673 Could I have a way to quote data$balance[data$state == 'AR'] in general, where balance=oldbalance, state=oldstate when data=dataa, and balance = newbalance, state = newstate when data=datab ? Thanks very much! Cheers, Rebecca ---------------------------------------------------------------------- This message, and any attachments, is for the intended r...{{dropped:20}} ______________________________________________ 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.
