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 hope I made myself clear. Any hints on how to achieve this? Is there already a function that does it? All searches I did pointed me to data type frame to matrix conversion... Kind Regards, Michael Bach ______________________________________________ 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.