It was suggested that the 'NAs introduced by coercion' message might be warning me that my data are not what they should be. I checked this using str(PeaksMatrix), as suggested, and the data seem to be what I thought they were:
'data.frame': 335 obs. of 127 variables: $ Code : Factor w/ 335 levels "A1MR","A1MU",..: 1 2 3 4 5 6 7 8 9 10 ... $ P3.70 : num 0 0 0 0 0 0 0 0 0 0 ... $ P3.97 : num 0 0 0 0 0 0 0 0 0 0 ... $ P4.29 : num 0 0 0 0 0 0 0 0 0 0 ... $ P4.90 : num 0 0 0 0 0 0 0 0 0 0 ... $ P6.30 : num 0 0 0 0 0 0 0 0 0 0 ... $ P6.45 : num 7.73 0 0 0 0 0 4.03 0 0 0 ... $ P6.55 : num 0 0 0 0 0 0 0 0 0 0 ... ... I do have 335 observations, 127 variables that are named P3.70, 3.97, P4.29, etc.. This was a relief, but I still don't know whether the distance matrix is what it should be. I tried 'str(dist.PxMx)', which is the name of my distance matrix, but I get something that has not much meaning to me, an unexperienced R user: Class 'dist' atomic [1:55945] 329.6 194.9 130.1 70.7 116.9 ... ..- attr(*, "Size")= int 335 ..- attr(*, "Labels")= chr [1:335] "1" "2" "3" "4" ... ..- attr(*, "Diag")= logi FALSE ..- attr(*, "Upper")= logi FALSE ..- attr(*, "method")= chr "euclidean" ..- attr(*, "call")= language dist(x = PeaksMatrix, method = "euclidean", diag = FALSE, upper = FALSE, p = 2) Any more suggestions, please? Silvia Lomascolo wrote: > > I work with Windows and use R version 2.4.1. I am JUST starting to learn > this program... > > I get this warning message 'NAs introduced by coercion' while trying to > build a distance matrix (to be analyzed with NMDS later) from a 336 x 100 > data matrix. The original matrix has lots of zeros and no missing values, > but I don't think this should matter. > > I searched this forum and people have suggested that the warning should be > ignored but when I try to print the distance matrix I only get the row > numbers (the matrix seems to be 'empty') and I'm not being able to judge > whether the matrix worked or not. > > To get the distance matrix I wrote: > dist.PxMx <- dist (PeaksMatrix, method='euclidean', diag=FALSE, > upper=FALSE) > > I tried including the p argument (included in the help for dist()) and > leaving it out, but that didn't seem to change anything. I think that's > required for one distance measure though, not for euclidean dist. > > Should I really ignore this warning? If so, why am I not being able to see > the distance matrix? > -- View this message in context: http://www.nabble.com/NAs-introduced-by-coercion-in-dist%28%29-tf3680727.html#a10286882 Sent from the R help mailing list archive at Nabble.com. ______________________________________________ R-help@stat.math.ethz.ch 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.
