r - 多次有效地子集 data.table

Question

我有这种格式的数据

> data = data.table(id = 1:10, date = seq(as.Date("2016-01-01"), by = 1, length = 10))
> data
    id       date
 1:  1 2016-01-01
 2:  2 2016-01-02
 3:  3 2016-01-03
 4:  4 2016-01-04
 5:  5 2016-01-05
 6:  6 2016-01-06
 7:  7 2016-01-07
 8:  8 2016-01-08
 9:  9 2016-01-09
10: 10 2016-01-10

我有另一个矩阵，它是我希望执行的查询/子集。

> query = data.table(id = c(1,4,7), date_start = c("2016-01-01", "2016-01-01", "2016-01-01"), date_end = c("2016-01-04", "2016-01-02", "2016-01-03"))
> query
   id date_start   date_end
1:  1 2016-01-01 2016-01-04
2:  4 2016-01-01 2016-01-02
3:  7 2016-01-01 2016-01-03

我想做这样的事情:

subset(data, (id == query[1] & date > date_start[1] & date < date_end[1]) | 
       (id == query[2] & date > date_start[2] & date < date_end[2]) |
       (id == query[3] & date > date_start[3] & date < date_end[3]))

有没有不使用for循环和rbinding结果自动生成子集查询的方法。

谢谢

Answer 1

如果我们稍微转换一下 OP 的数据就可以得到

library(data.table)
data = setDT(structure(list(id = 1:10, date = structure(16801:16810, class = c("IDate", 
"Date")), date2 = structure(16801:16810, class = c("IDate", "Date"
))), .Names = c("id", "date", "date2"), row.names = c(NA, -10L
), class = c("data.table", "data.frame"), sorted = c("id", 
"date", "date2")))

query = setDT(structure(list(id = c(1, 4, 7), date_start = 
structure(c(16801L, 
16801L, 16801L), class = c("IDate", "Date")), date_end = structure(c(16804L, 
16802L, 16803L), class = c("IDate", "Date"))), .Names = c("id", 
"date_start", "date_end"), row.names = c(NA, -3L), class = c("data.table", 
"data.frame"), sorted = c("id", 
"date_start", "date_end")))

...然后我们可以像这样使用foverlaps

foverlaps(data, query, nomatch=0)
#    id date_start   date_end       date      date2
# 1:  1 2016-01-01 2016-01-04 2016-01-01 2016-01-01

对于这种方法，我认为需要在合并之前采取这些步骤:

• 将所有日期设为IDate
• 在主数据中创建一个额外的日期列
• 在每个表上设置键