[R] How to add a variable to a dataframe whose values are conditional upon the values of an existing variable
eriki at ccbr.umn.edu
Fri Feb 26 20:38:02 CET 2010
You mention ifelse, so for completeness, I will show you a solution that
should work with that. There are other plenty of other possibilities
though, I am sure. The follow is not tested..
Assume 'my.df' is your data.frame, containing a variable "DOW".
my.df$DOW1 <- ifelse(my.df$DOW == "SAT", 1,
ifelse(my.df$DOW == "SUN", 2,
ifelse(my.df$DOW == "MON", 3,
ifelse(my.df$DOW == "TUE", 4,
ifelse(my.df$DOW == "WED", 5,
ifelse(my.df$DOW == "THU", 6,
(don't know if the number of closing ")" is right, but you get the idea...
Steve Matco wrote:
> Hi everyone,
> I am at my wits end with what I believe would be considered simple by a more experienced R user. I want to know how to add a variable to a dataframe whose values are conditional on the values of an existing variable. I can't seem to make an ifelse statement work for my situation. The existing variable in my dataframe is a character variable named DOW which contains abbreviated day names (SAT, SUN, MON.....FRI). I want to add a numerical variable named DOW1 to my dataframe that will take on the value 1 if DOW equals "SAT", 2 if DOW equals "SUN", 3 if DOW equals "MON",.....,7 if DOW equals "FRI".
> I know this must be a simple problem but I have searched everywhere and tried everything I could think of. Any help would be greatly appreciated.
> Thank you,
> R-help at r-project.org mailing list
> PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
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