Find rows with time between two values in R - r

Question

I have a dataframe temp which looks like the following:
Time Count Colour
01:02:30 11.000000 Red
17:05:49 52.000000 White
04:06:07 4.000000 Blue
01:07:03 30.000000 Red
20:08:30 4.000000 Yellow
The Time was initially an ISODate do I stripped it off to get the time, which is what I wanted, using the code below.
temp$Time = parse_iso_8601(temp$Time)
temp$Time <- as.POSIXlt(temp$Time)
library(chron)
temp$Time=times(format(temp$Time, format="%H:%M:%S"))
Now, I wish to find rows with time between 02:00:00 and 05:00:00. Can you please suggest how this can be done? Thanks!

Answer 1

Here is my try,
temp <- read.table(text = "Time Count Colour
01:02:30 11.000000 Red
17:05:49 52.000000 White
04:06:07 4.000000 Blue
01:07:03 30.000000 Red
20:08:30 4.000000 Yellow", header = TRUE)
library(chron)
temp$Time <- times(format(temp$Time, format="%H:%M:%S"))
temp[temp$Time >= 2/24 & temp$Time <= 5/24, ]
Output:
> temp[temp$Time >= 2/24 & temp$Time <= 5/24, ]
Time Count Colour
3 04:06:07 4 Blue
The logic:
The code below shows that the function times should be mapping [00:00:00, 23:59:59.999...) to [0, 1)
> as.numeric(times(paste(0:23, ":00:00", sep = "")))
[1] 0.00000000 0.04166667 0.08333333 0.12500000 0.16666667 0.20833333
[7] 0.25000000 0.29166667 0.33333333 0.37500000 0.41666667 0.45833333
[13] 0.50000000 0.54166667 0.58333333 0.62500000 0.66666667 0.70833333
[19] 0.75000000 0.79166667 0.83333333 0.87500000 0.91666667 0.95833333
Thus, to find if the Time is between 02:00:00 and 05:00:00, you can check whether it is greater or equal to 2/24 and smaller or equal to 5/25.
The gap problem:
Not sure if it is what you want.
Assume temp is ordered by date and time, like the one below
library(chron)
temp <- data.frame(
Record = 1:8,
Day = c(1, 1, 1, 1, 1, 2, 2, 2),
Time = c("01:02:30", "01:07:03", "04:06:07", "17:05:49", "20:08:30", "02:00:00", "02:15:00", "04:07:00")
)
temp$Time <- times(format(temp$Time, format="%H:%M:%S"))
> temp
Record Day Time
1 1 1 01:02:30
2 2 1 01:07:03
3 3 1 04:06:07
4 4 1 17:05:49
5 5 1 20:08:30
6 6 2 02:00:00
7 7 2 02:15:00
8 8 2 04:07:00
R code to do your task:
temp$Gap <- 24 * (c(NA, diff(temp$Time)) + c(NA, diff(temp$Day) > 0))
temp$Gap3hr <- temp$Gap >= 3 # 3 hour gap
temp$HourFromFirst <- 24 * (temp$Time - temp$Time[1]) + 24 * (temp$Day - temp$Day[1])
tempSelected <- lapply(which(temp$Gap3hr == TRUE), function(i) {
BeforeGap1hr <- (temp$HourFromFirst[i - 1] - temp$HourFromFirst) <= 1 & (temp$HourFromFirst[i - 1] - temp$HourFromFirst) >= 0
AfterGap1hr <- (temp$HourFromFirst - temp$HourFromFirst[i]) <= 1 & (temp$HourFromFirst - temp$HourFromFirst[i]) >= 0
temp[BeforeGap1hr | AfterGap1hr, ]
}
)
Output:
> tempSelected
[[1]]
Record Day Time Gap Gap3hr HourFromFirst
3 3 1 04:06:07 2.984444 FALSE 3.060278
4 4 1 17:05:49 12.995000 TRUE 16.055278
[[2]]
Record Day Time Gap Gap3hr HourFromFirst
4 4 1 17:05:49 12.995000 TRUE 16.05528
5 5 1 20:08:30 3.044722 TRUE 19.10000
[[3]]
Record Day Time Gap Gap3hr HourFromFirst
5 5 1 20:08:30 3.044722 TRUE 19.10000
6 6 2 02:00:00 5.858333 TRUE 24.95833
7 7 2 02:15:00 0.250000 FALSE 25.20833