On 26-Aug-04 Kevin Wang wrote: > Hi, > > If a value like 8e-04 is in a data frame, is the following behaviour > normal? > > > final.df > Chr P.values > 1 1 0.0379 > 2 6 0.068 > 3 2 0.0025 > 4 13 8e-04 > 5 14 0.0244 > 6 3 0.0279 > 7 4 0.1561 > 8 5 0.9261 > 9 7 0.0011 > 10 9 0.5125 > 11 10 0.2196 > 12 11 0.6457 > 13 18 0.9272 > > > final.sorted <- data.frame(final.df[order(final.df$P.values), ], > + row.names = 1:13) > > final.sorted > Chr P.values > 1 7 0.0011 > 2 2 0.0025 > 3 14 0.0244 > 4 3 0.0279 > 5 1 0.0379 > 6 6 0.068 > 7 4 0.1561 > 8 10 0.2196 > 9 9 0.5125 > 10 11 0.6457 > 11 5 0.9261 > 12 18 0.9272 > 13 13 8e-04 > > I'd think 8e-04 should be the smallest value...? It's R 1.9.1 on > Windows XP if that helps.
It looks to me as though you have managed somehow to get the "numerical" data into the dataframe as character strings, which will be sorted alphabetically rather than numerically by 'order'. The first clue is that if you read in a (e.g.) CSV file with your original data as displayed above, then print it out with 'final.df', then the value "8e-04" shows as "0.008". Sorting this DF with your command shows "0.008" in its proper place, at the top of the list. The next clue is that if you then assign final final.df[4,2] with final.df[4,2]<-"8e-04" and then sort the DF in the same way, then "8e-04" comes out where you found it, i.e. at the bottom of the list. This is consistent with alphabetical sorting, since "8" follows "0" (and in any case "e" follows "."). So I think you should have a look at how the data got into final.df in the first place. Good luck, Ted. -------------------------------------------------------------------- E-Mail: (Ted Harding) <[EMAIL PROTECTED]> Fax-to-email: +44 (0)870 167 1972 Date: 26-Aug-04 Time: 09:43:10 ------------------------------ XFMail ------------------------------ ______________________________________________ [EMAIL PROTECTED] mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html
