I am sure this is easy but I am not finding a function to do this. I have two columns in a matrix. The first column contains multiple entries of numbers from 1 to 100 (i.e. 10 ones, 8 twos etc.). The second column contains unique numbers. I want to sum the numbers in column two based on the indexed values in column one (e.g. sum of all values in column two associated with the value 1 in column one). I would like two columns in return - the indexed value in column one (i.e. this time no duplicates) and the sum in column two.
How do I do this? -- View this message in context: http://old.nabble.com/Sum-over-indexed-value-tp26376359p26376359.html Sent from the R help mailing list archive at Nabble.com. ______________________________________________ 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.
