r - Inner_join 有两个条件和区间内的区间条件

Question

尝试根据多个条件和时间间隔条件加入 2 个数据帧，如下例所示:

# two sample dataframes with time intervals
df1 <- data.frame(key1 = c("a", "b", "c", "d", "e"),
                   key2 = c(1:5),
                   time1 = as.POSIXct(hms::as.hms(c("00:00:15", "00:15:15", "00:30:15", "00:40:15", "01:10:15"))),
                   time2 = as.POSIXct(hms::as.hms(c("00:05:15", "00:20:15", "00:35:15", "00:45:15", "01:15:15")))) %>% 
  mutate(t1 = interval(time1, time2)) %>%
  select(key1, key2, t1)  

df2 <- data.frame(key1 = c("b", "c", "a", "e", "d"),
                   key2 = c(2, 6, 1, 8, 5),
                   sam1 = as.POSIXct(hms::as.hms(c("00:21:15", "00:31:15", "00:03:15", "01:20:15", "00:43:15"))),
                   sam2 = as.POSIXct(hms::as.hms(c("00:23:15", "00:34:15", "00:04:15", "01:25:15", "00:44:15")))) %>% 
mutate(t2 = interval(sam1, sam2)) %>%
select(key1, key2, t2)

首先需要对应的是 key1 和 key2 列，这可以通过以下方式完成(产生错误):

df <- inner_join(df1, df2, by = c("key1", "key2"))

但是加入时还有一个条件需要检查，那就是时间间隔t2是否在t1之内。我可以像这样手动执行此操作:

 df$t2 %within% df$t1

我猜错误是由于以间隔连接数据帧而导致的，这可能不是正确的方法，这就是出现错误的原因。

# desired dataframe
df <- data.frame(key1 = c("a", "b"), key2 = c(1,2), time_condition = c(TRUE, FALSE))

如果 t1 是从 "00:00:15"到 "00:05:15" 那么相应的 t2 是 "00:03:15"到 "00: 04:15" 将在时间间隔 t1 内。如果 t2 在 t1 内，这将导致 time_condition 列为 TRUE，否则为 FALSE。

Answer 1

使用data.table，可以边join边操作。这是一个例子

library(data.table)
df2[df1, # left join
    .(time_condition = sam1 > time1 & sam2 < time2), # condition while joining
    on = .(key1, key2), # keys
    by = .EACHI, # check condition per join
    nomatch = 0L] # make it an inner join

#    key1 key2 time_condition
# 1:    a    1           TRUE
# 2:    b    2          FALSE

---

# your data generated using data.table

df1 <- data.table(key1 = c("a", "b", "c", "d", "e"),
                  key2 = c(1:5),
                  time1 = as.ITime(c("00:00:15", "00:15:15", "00:30:15", "00:40:15", "01:10:15")),
                  time2 = as.ITime(c("00:05:15", "00:20:15", "00:35:15", "00:45:15", "01:15:15"))) 
df2 <- data.table(key1 = c("b", "c", "a", "e", "d"),
                  key2 = c(2, 6, 1, 8, 5),
                  sam1 = as.ITime(c("00:21:15", "00:31:15", "00:03:15", "01:20:15", "00:43:15")),
                  sam2 = as.ITime(c("00:23:15", "00:34:15", "00:04:15", "01:25:15", "00:44:15")))