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假设我有一个包含开始和结束时间列、一个测量列和一个测量时间列的数据框，如下所示：

     start         end    value                time
   9:01:00     9:02:00     30.6  2013-03-25 9:05:00
   9:01:00     9:02:00     30.8  2013-03-25 9:15:00
   9:46:00     9:46:00     28.2  2013-03-25 9:43:00
   9:46:00     9:46:00     28.9  2013-03-25 9:53:00
  10:54:00    10:59:00     13.4 2013-03-25 10:56:00
  10:54:00    10:59:00     13.8 2013-03-25 11:56:00

如何将此数据框子集化为仅包含时间列在开始和结束时间或开始时间前十分钟和结束时间后十分钟内的行。我任意选择十分钟，并且想知道如何在开始和结束时间之前和之后的任何时间内执行此操作。

生成的数据框如下： 

     start         end    value                time
   9:01:00     9:02:00     30.6  2013-03-25 9:05:00
   9:46:00     9:46:00     28.2  2013-03-25 9:43:00
   9:46:00     9:46:00     28.9  2013-03-25 9:53:00
  10:54:00    10:59:00     13.4 2013-03-25 10:56:00

除了从开始/结束列条目中减去/添加 x 分钟数，然后根据时间列是否位于这些扩展窗口之间进行子集之外，还有其他方法吗？

目前，我已将时间列转换为 POSIXlt 格式。不幸的是，这在开始和结束列中给出了今天的日期。

这是第一个数据帧的 dput：

structure(list(start = structure(list(sec = c(0, 0, 0, 0, 0, 
0), min = c(1L, 1L, 46L, 46L, 54L, 54L), hour = c(9L, 9L, 9L, 
9L, 10L, 10L), mday = c(7L, 7L, 7L, 7L, 7L, 7L), mon = c(7L, 
7L, 7L, 7L, 7L, 7L), year = c(113L, 113L, 113L, 113L, 113L, 113L
), wday = c(3L, 3L, 3L, 3L, 3L, 3L), yday = c(218L, 218L, 218L, 
218L, 218L, 218L), isdst = c(1L, 1L, 1L, 1L, 1L, 1L)), .Names = c("sec", 
"min", "hour", "mday", "mon", "year", "wday", "yday", "isdst"
), class = c("POSIXlt", "POSIXt")), end = structure(list(sec = c(0, 
0, 0, 0, 0, 0), min = c(2L, 2L, 46L, 46L, 59L, 59L), hour = c(9L, 
9L, 9L, 9L, 10L, 10L), mday = c(7L, 7L, 7L, 7L, 7L, 7L), mon = c(7L, 
7L, 7L, 7L, 7L, 7L), year = c(113L, 113L, 113L, 113L, 113L, 113L
), wday = c(3L, 3L, 3L, 3L, 3L, 3L), yday = c(218L, 218L, 218L, 
218L, 218L, 218L), isdst = c(1L, 1L, 1L, 1L, 1L, 1L)), .Names = c("sec", 
"min", "hour", "mday", "mon", "year", "wday", "yday", "isdst"
), class = c("POSIXlt", "POSIXt")), value = c(30.6, 30.8, 28.2, 
28.9, 13.4, 13.8), time = structure(list(sec = c(0, 0, 0, 0, 
0, 0), min = c(5L, 15L, 43L, 53L, 56L, 56L), hour = c(9L, 9L, 
9L, 9L, 10L, 11L), mday = c(25L, 25L, 25L, 25L, 25L, 25L), mon = c(2L, 
2L, 2L, 2L, 2L, 2L), year = c(113L, 113L, 113L, 113L, 113L, 113L
), wday = c(1L, 1L, 1L, 1L, 1L, 1L), yday = c(83L, 83L, 83L, 
83L, 83L, 83L), isdst = c(1L, 1L, 1L, 1L, 1L, 1L)), .Names = c("sec", 
"min", "hour", "mday", "mon", "year", "wday", "yday", "isdst"
), class = c("POSIXlt", "POSIXt"))), .Names = c("start", "end", 
"value", "time"), row.names = c(NA, -6L), class = "data.frame")

这是第二个数据帧的输入

structure(list(start = structure(list(sec = c(0, 0, 0, 0), min = c(1L, 
46L, 46L, 54L), hour = c(9L, 9L, 9L, 10L), mday = c(7L, 7L, 7L, 
7L), mon = c(7L, 7L, 7L, 7L), year = c(113L, 113L, 113L, 113L
), wday = c(3L, 3L, 3L, 3L), yday = c(218L, 218L, 218L, 218L), 
    isdst = c(1L, 1L, 1L, 1L)), .Names = c("sec", "min", "hour", 
"mday", "mon", "year", "wday", "yday", "isdst"), class = c("POSIXlt", 
"POSIXt")), end = structure(list(sec = c(0, 0, 0, 0), min = c(2L, 
46L, 46L, 59L), hour = c(9L, 9L, 9L, 10L), mday = c(7L, 7L, 7L, 
7L), mon = c(7L, 7L, 7L, 7L), year = c(113L, 113L, 113L, 113L
), wday = c(3L, 3L, 3L, 3L), yday = c(218L, 218L, 218L, 218L), 
    isdst = c(1L, 1L, 1L, 1L)), .Names = c("sec", "min", "hour", 
"mday", "mon", "year", "wday", "yday", "isdst"), class = c("POSIXlt", 
"POSIXt")), value = c(30.6, 28.2, 28.9, 13.4), time = structure(list(
    sec = c(0, 0, 0, 0), min = c(5L, 43L, 53L, 56L), hour = c(9L, 
    9L, 9L, 10L), mday = c(25L, 25L, 25L, 25L), mon = c(2L, 2L, 
    2L, 2L), year = c(113L, 113L, 113L, 113L), wday = c(1L, 1L, 
    1L, 1L), yday = c(83L, 83L, 83L, 83L), isdst = c(1L, 1L, 
    1L, 1L)), .Names = c("sec", "min", "hour", "mday", "mon", 
"year", "wday", "yday", "isdst"), class = c("POSIXlt", "POSIXt"
))), .Names = c("start", "end", "value", "time"), row.names = c(NA, 
-4L), class = "data.frame")
4

2 回答 2

2

重新创建没有乐趣，但答案应该很简单：

data[with(data, time > start - 10*60 & time < end + 10*60),]

这假设start,end和time对象实际上都是可比较的（即相应的年份和日期） - 否则只需将对应于一天中的时间的子字符串转换为 POSIX。

更新：好的，由于您的日期已关闭，您需要重新创建它们以“同步”，例如：

data$start <- as.POSIXct(substr(data$start,12,19), format="%H:%M:%S")
data$end <- as.POSIXct(substr(data$end,12,19), format="%H:%M:%S")
data$time <- as.POSIXct(substr(data$time,12,19), format="%H:%M:%S")

现在，上面的行给出了你想要的。可能，您应该小心如何从原始数据中编码 POSIX。此外，对于大多数应用程序，POSIXct 可能比 POSIXlt 更受欢迎——其中每个元素都是一个列表。这可能会阻碍（或减慢）稍后的某些操作。

于 2013-08-07T04:20:26.453 回答
1

基于@EliGurarie 的回答：

#dat <- ....see original question

将时间转换为POSIX表示并进行数学运算：

datestem <- as.character(as.Date(dat$time))
dat$start <- as.POSIXct(paste(datestem,format(dat$start,"%H:%M:%S")))
dat$end <- as.POSIXct(paste(datestem,format(dat$end,"%H:%M:%S")))

dat[
     with(
      dat,
      difftime(start,time,units="mins") > -10 &
      difftime(end,time,units="mins") < 10
     ),
   ]

或者，使用一些舍入和一些中间变量：

min10 <- 10/(60*24)
ds <- difftime(dat$start,dat$time,units="days")
ds <- dd - round(dd) 
de <- difftime(dat$end,dat$time,units="days")
de <- de - round(de) 

dat[ds > -min10 & de < min10,]
于 2013-08-07T06:13:57.083 回答