?aggregate或许有些帮助
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text <- "V1 V2 V3<br />
2006 1 1871<br />
2006 2 1828<br />
2006 3 2126<br />
2006 4 2172<br />
2006 5 2340<br />
2006 6 2397<br />
2006 7 2389<br />
2006 8 2444<br />
2006 9 2430<br />
2006 10 2490<br />
2006 11 2554<br />
2006 12 2736<br />
2007 1 2404<br />
2007 2 2289<br />
2007 3 2604<br />
2007 4 2646<br />
2007 5 2741<br />
2007 6 2889<br />
2007 7 2811<br />
2007 8 2796<br />
2007 9 2890<br />
2007 10 2854<br />
2007 11 2878<br />
2007 12 2958"<br />
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text <- gsub(" +", " ", text)<br />
tab <- read.table(textConnection(text), sep=" ", head=TRUE)<br />
names(tab)<br />
attach(tab)<br />
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aggregate(cbind(V3), list(Month=V2), function(x) {paste(paste(x, collapse=","), sum(x), sep=",")})<br />
