Hi, With this data.frame:
> class(rwl) [1] "data.frame" >rwl 0028002F 0028013F 0028032F 1833 3.39 NA NA 1834 3.09 NA NA 1835 3.05 NA NA 1836 3.31 NA NA 1837 2.26 NA NA > colnames(rwl) [1] "0028002F" "0028013F" "0028032F" Ok.... > colnames(rwl[,1]) NULL why?? I expect: "0028002F" Thanks in advance, Alfredo ______________________________________________ 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.