Petr PIKAL <petr.pi...@precheza.cz> writes: > Hi > > r-help-boun...@r-project.org napsal dne 19.04.2011 09:46:47: > >> Dear R Users, >> >> Lets assume I have this data frame: >> >> x y z >> 1 1.00 5 0.5 >> 2 1.02 5 0.7 >> 3 1.04 7 0.1 >> 4 1.06 9 0.4 >> >> x and y columns are sorted and the values not necessarily integers. z >> values are not sorted. Now I would like to create a matrix out of this >> with x as first column values and y as first row values. Matrix element >> a_11 shall be left NA. The a_ij should have the z value for the >> corresponding x and y pair. The result shall be some sort of a grid and >> then e.g. look like: >> >> [,1] [,2] [,3] [,4] [,5] >> [1,] NA 5 6 7 9 (y) >> [2,] 1.00 0.5 NA NA NA >> [3,] 1.02 0.7 NA NA NA >> [4,] 1.04 NA NA 0.1 NA >> [5,] 1.06 NA NA NA 0.4 >> (x) >> >> This example is just for illustration. The resulting matrix should have >> more numeric values than NA's. > > I am not sure if this is the solution you want > > tab<-xtabs(z~x+y, data=df) > tab[tab==0]<-NA >
This looks right, but the resulting table does not have rows == columns and there are also no missing values (0 or NA) which should be there. I think I did not make myself clear, please see also my reply to the previous answer to my question by David Winsemius. Thanks for your reply though! ______________________________________________ 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.
