R 循环遍历一个表以获取另一个表中的计数

在R中，我有一个种子表，如下所示：

种子盘

|========|================|
| date   | classification |
|========|================|
| 201501 | A              |
| 201501 | A              |
| 201501 | A              |
| 201502 | B              |
| 201502 | B              |
| 201502 | B              |
| ...    | ...            |

数据表如下所示

数据：

我正在编写下面的代码，以获取每个月的“活动观察”数量以及种子表中的分类。活动观察是一种观察，其在种子表中行的

创建日期=月份

：

n <- nrow(seed_table)
num_obs <- numeric(n)
for (row in 1:n) {
    num_obs[row] <- (sum(
        data$Created_Date >= seed_table[row, "date"] &
            data$End_Date <= seed_table[row, "date"] &
            data$classification == seed_table[row, "classification"]))
    cat(n - row)
}  

---

n正如@eric fail所建议的，您应该使用
dput（）
来共享您的数据。例如：

seed_table <- structure(list(
  date = c(201501L, 201501L, 201502L), 
  classification = structure(
    c(1L, 1L, 2L), .Label = c("A", "B"), class = "factor")), 
  .Names = c("date", "classification"), 
  row.names = c(1L, 2L, 4L), class = "data.frame")
data <- structure(list(
  ID = 1:6, 
  Create_Date = c(201501L, 201501L, 201502L, 201412L, 201412L, 201502L), 
  End_Date = c(201601L, 201605L, 201601L, 201501L, 201502L, 201503L), 
  classification = structure(c(1L, 2L, 2L, 1L, 2L, 1L), 
    .Label = c("A", "B"), class = "factor")), 
  .Names = c("ID", "Create_Date", "End_Date", "classification"), 
  class = "data.frame", row.names = c(NA, -6L))

请注意，您的代码中有一些错误。你提到的是
Created_Date
，而不是
Create_Date
，并且（我相信）你有自己的不平等（
=
和
请提交一个最小可复制的示例。请参阅：。具体来说，你应该使用
dput（）
阅读和汇总：，在R中共享你的（最小可复制）数据
seed_table <- structure(list(
  date = c(201501L, 201501L, 201502L), 
  classification = structure(
    c(1L, 1L, 2L), .Label = c("A", "B"), class = "factor")), 
  .Names = c("date", "classification"), 
  row.names = c(1L, 2L, 4L), class = "data.frame")
data <- structure(list(
  ID = 1:6, 
  Create_Date = c(201501L, 201501L, 201502L, 201412L, 201412L, 201502L), 
  End_Date = c(201601L, 201605L, 201601L, 201501L, 201502L, 201503L), 
  classification = structure(c(1L, 2L, 2L, 1L, 2L, 1L), 
    .Label = c("A", "B"), class = "factor")), 
  .Names = c("ID", "Create_Date", "End_Date", "classification"), 
  class = "data.frame", row.names = c(NA, -6L))

m1 <- outer(seed_table$date, data$Create_Date, ">=")
m2 <- outer(seed_table$date, data$End_Date, "<=")
m3 <- outer(seed_table$classification, data$classification, "==")
m <- m1 & m2 & m3
num_obs <- apply(m, 1, sum)