Dear all, I have 9 data frames, and I'm simply trying to sum the values of column 3 (on a row-by-row basis). However, there are a slightly different number of rows in each data frame, so I'm receiving the following error: "Error in Ops.data.frame(mrunoff_207101[3], mrunoff_207102[3]) : ? + only defined for equally-sized data frames". Here is what I'm attempting to do:
arunoff_2071 <- cbind(mrunoff_207101[1:2], (mrunoff_207101[3] + mrunoff_207102[3] + mrunoff_207103[3] + mrunoff_207104[3] + mrunoff_207105[3] + mrunoff_207106[3] + mrunoff_207107[3] + mrunoff_207108[3] + mrunoff_207109[3]))
Is there an easy way of summing based on congruent values in columns 1 and 2? The only way I can think of would be to use merge, but this would involve doing this for every pair of data frames. The data for each data frame look like this:
head(mrunoff_207101)
? Latitude Longitude????????? FPC 1???? 5.75????? 0.25 0.0112384744 2???? 6.25????? 0.25 0.0019959067 3???? 6.75????? 0.25 0.0003245941 4???? 7.25????? 0.25 0.0011973676 5???? 7.75????? 0.25 0.0001062602 6???? 8.25????? 0.25 0.0451578423 Any suggestions on how to achieve this easily will be very welcome. Many thanks, Steve