Hi, library(reshape2) dcast(DF,a~b,value.var="c",sum) # a 1 2 3 4 #1 1 900 100 500 300 #2 2 300 900 200 100 A.K. ----- Original Message ----- From: Benjamin Gillespie <gy...@leeds.ac.uk> To: "r-help@r-project.org" <r-help@r-project.org> Cc: Sent: Monday, February 4, 2013 4:29 AM Subject: [R] Script for conditional sums of vectors
Hi guys, I hope you can help me with this (probably) simple query: I have a data frame: -------------------------- a=c(1,1,1,1,1,1,2,2,2,2,2,2) b=c(1,1,1,2,3,4,1,1,2,2,3,4) c=c(400,200,300,100,500,300,200,100,500,400,200,100) data=data.frame(a=a,b=b,c=c) -------------------------- And I would like to get the following output: -------------------------- b a 1 2 3 4 1 900 100 500 300 2 300 900 200 100 -------------------------- The values in the output represent the sum of values "c" in data frame "data", for each "a" and "b" combination. For example, where "a" = 1 and "b" = 1, the output is 400+200+300 = 900. Please would anyone be able to provide a script to create my desired output? Many thanks in advance, Ben Gillespie Research Postgraduate School of Geography University of Leeds Leeds LS2 9JT ______________________________________________ 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. ______________________________________________ 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.
