小编heo*_*heo的帖子

我有一个看起来像这样的数据集:

 Type Age   count1  count2  Year   Pop1   Pop2  TypeDescrip
  A   35    1        1      1990   30000  50000  alpha                                 
  A   35    3        1      1990   30000  50000  alpha 
  A   45    2        3      1990   20000  70000  alpha 
  B   45    2        1      1990   20000  70000  beta
  B   45    4        5      1990   20000  70000  beta 

我想添加在Type和Age列中匹配的行的计数.理想情况下,我最终会得到一个如下所示的数据集:

 Type  Age  count1  count2  Year   Pop1   Pop2  TypeDescrip 
  A   35    4        2      1990   30000  50000  alpha 
  A   45    2        3      1990   20000  70000  alpha 
  B   45    6        6      1990   20000 …

假设我有两个数据集.一个包含具有开始/结束日期的促销列表,另一个包含每个程序的月度销售数据.

promotions = data.frame(
    start.date = as.Date(c("2012-01-01", "2012-06-14", "2012-02-01", "2012-03-31", "2012-07-13")), 
    end.date = as.Date(c("2014-04-05", "2014-11-13", "2014-02-25", "2014-08-02", "2014-09-30")), 
    program = c("a", "a", "a", "b", "b"))

sales = data.frame(
    year.month.day = as.Date(c("2013-02-01", "2014-09-01", "2013-08-01", "2013-04-01", "2012-11-01")), 
    program = c("a", "b", "a", "a", "b"), 
    monthly.sales = c(200, 200, 200, 400, 200))

注意,sales$year.month.day用于表示年/月.包括日,因此R可以更简单地将列视为日期对象的向量,但它与实际销售无关.

我需要确定每个程序每月发生的促销数量.这是一个产生我想要的输出的循环示例:

sales$count = rep(0, nrow(sales))
sub = list()
for (i in 1:nrow(sales)) {
  sub[[i]] = promotions[which(promotions$program == sales$program[i]),]
  if (nrow(sub[[i]]) > 1) {
    for (j in 1:nrow(sub[[i]])) { …