From: [EMAIL PROTECTED] > > Now that people have answered Monica's query, can someone help me?!! > See below. > > On 13-Mar-08 13:36:03, Monica Pisica wrote: > > > > Hi, > > > > I am trying to get percentages in a more elegant way. I have a > > data.frame with locations and values (counts) of species at that > > location. Each location is repeated for each species i have > values for > > and i would like to get percentages of each species at that > location. I > > am not sure if i am clear in my explanations so i will paste my code > > below: > > > >##################### > > > >> x > > locat val > > 1 a 5 > > 2 b 5 > > 3 b 15 > > 4 c 5 > > 5 c 20 > > 6 c 5 > > 7 c 10 > > 8 d 5 > > 9 d 15 > > 10 d 10 > > With Monica's dataframe as above, the answer would be 100*x[,1]/z > where we want z to be c(5,20,20,40,40,40,40,30,30,30). > > So, intending to give Monica a helpful answer, I tried > > > apply(x,1,function(y) sum(x[x[,1]==y,2])) > 1 2 3 4 5 6 7 8 9 10 > 5 15 15 30 30 30 30 15 15 15 > > and similarly > > > apply(x,1,function(y) sum(x$val[x$locat==y])) > 1 2 3 4 5 6 7 8 9 10 > 5 15 15 30 30 30 30 15 15 15 > > > So why didn't this work? Where's my blind spot? Indeed, why > did it gives the results it did?
One strategy is similar to what the piano teacher ask my son to try: break it into small pieces. apply() works on slices of the data, so take a slice where the answer wasn't what you expected; e.g., the last row of x. What gets passed into the anonymous function is the 10th row of x, namely c(4, 10) (note that apply() converts its first argument to a matrix or array). so what would you get when you test for equality to that? Andy > With thanks, > Ted. > > -------------------------------------------------------------------- > E-Mail: (Ted Harding) <[EMAIL PROTECTED]> > Fax-to-email: +44 (0)870 094 0861 > Date: 13-Mar-08 Time: 14:15:34 > ------------------------------ XFMail ------------------------------ > > ______________________________________________ > 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. > > > ------------------------------------------------------------------------------ Notice: This e-mail message, together with any attachme...{{dropped:15}} ______________________________________________ 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.
