Hello and thank you in advance for your assistance,
(PLEASE Note Comments section for additional insight: i.e. the cost column in the example below was added to this question; Simon, provides a great answer, but the cost column itself is not represented in the data response from him, although the function he provides works with the cost column)
I have a data set, lets call it 'data' which looks like this
NAME DATE COLOR PAID COST
Jim 1/1/2013 GREEN 150 100
Jim 1/2/2013 GREEN 50 25
Joe 1/1/2013 GREEN 200 150
Joe 1/2/2013 GREEN 25 10
What I would like to do is sum the PAID (and COST) elements of the records with the same NAME value and reduce the number of rows (as in this example) to 2, such that my new data frame looks like this:
NAME DATE COLOR PAID COST
Jim 1/2/2013 GREEN 200 125
Joe 1/2/2013 GREEN 225 160
As far as the dates are concerned, I don't really care about which one survives the summation process.
I've gotten as far as rowSums(data), but I'm not exactly certain how to use it. Any help would be greatly appreciated.
aggregate
is the function you are looking for:
aggregate( cbind( PAID , COST ) ~ NAME + COLOR , data = data , FUN = sum )
# NAME PAID
# 1 Jim 200
# 2 Joe 225