最简单的方式就是用list去处理，范例code如下：
Product = "Product1" #可自行输入产品编号
Month = "July" #可指定月份
data.l = lapply(1:10, function(k){
eval(parse(text=paste("read.csv(\"D:/year", k, ".csv\")", sep="")))
}
)
output.l = lapply(data.l, function(ll){
eval(parse(text=paste("subset(ll, ", "Month==\"", Month, "\", select = ",
Product, ")", sep="")))
}
)
output.fr = Reduce(data.frame, output.l)