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rdplyrdifftime

Calculating conditional cumulative time

Following the pointers from this question.

I'd like to calculate the cumulative time for all the Cats, by considering their respective last toggle status.

EDIT: I'd also want to check if the FIRST Toggle status of a Cat is Off and if it is so, for that specific cat, the time from midnight 00:00:00 till this first FIRST Off time should be added to its total conditional cumulative ontime.

Sample data:

       Time Cat Toggle
1  05:12:09  36 On
2  05:12:12 26R Off # First Toggle of this Cat happens to be Off, Condition met
3  05:12:15 26R On
4  05:12:16 26R Off
5  05:12:18  99 Off # Condition met
6  05:12:18  99 On
7  05:12:24  36 Off
8  05:12:26  36 On
9  05:12:29  80 Off # Condition met
10 05:12:30  99 Off
11 05:12:31  95 Off # Condition met
12 05:12:32  36 Off

Desired sample output:

  Cat Time(Secs)
1 36  21
2 26R 18733 # (=1+18732), 18732 secs to be added = total Sec from midnight till 05:12:12
3 99  18750 # (=12+18738), 18738 secs to be added = total Sec from midnight till 05:12:18
4 ..  ..

Any sort of help is appreciated.

Solution

  • A possible solution using :

    # load the 'data.table'-package, convert 'df' to a 'data.table'
# and 'Time'-column to a time-format
library(data.table)
setDT(df)[, Time := as.ITime(Time)]

# calculate the time-difference
df[, .(time.diff = sum((shift(Time, type = 'lead') - Time) * (Toggle == 'On'), na.rm = TRUE))
   , by = Cat]

    which gives:

       Cat time.diff
1:  36        21
2: 26R         1
3:  99        12
4:  80         0
5:  95         0

    In respons to your question in the comments, you could do:

    # create a new data.table with midnigth times for the categories where
# the first 'Toggle' is on "Off"
df0 <- df[, .I[first(Toggle) == "Off"], by = Cat
          ][, .(Time = as.ITime("00:00:00"), Cat = unique(Cat), Toggle = "On")]

# bind that to the original data.table; order on 'Cat' and 'Time'
# and then do the same calculation
rbind(df, df0)[order(Cat, Time)
               ][, .(time.diff = sum((shift(Time, type = 'lead') - Time) * (Toggle == 'On'), na.rm = TRUE))
                                 , by = Cat]

    which gives:

       Cat time.diff
1: 26R     18733
2:  36        21
3:  80     18749
4:  95     18751
5:  99     18750

    An alternative with base R (only original question):

    df$Time <- as.POSIXct(df$Time, format = "%H:%M:%S")

stack(sapply(split(df, df$Cat),
             function(x) sum(diff(x[["Time"]]) * (head(x[["Toggle"]],-1) == 'On'))))

    which gives:

      values ind
1      1 26R
2     21  36
3      0  80
4      0  95
5     12  99

    Or with the (only original question):

    library(dplyr)
library(lubridate)

df %>% 
  mutate(Time = lubridate::hms(Time)) %>% 
  group_by(Cat) %>% 
  summarise(time.diff = sum(diff(Time) * (head(Toggle, -1) == 'On'),
                            na.rm = TRUE))