Generate a column containing the time in minutes - in R

Question

in R

I have a data-frame with 24400 observations (rows). In this data-frame I have a column df$hours containing hours index (as shown below). Basically each hour is repeated over around ~ 60 times before passing to the next hour until reaching the 23rd hour then it goes back again to "o" (example below

df$hours

1] "00" "00" "00" "00" "00" "00" "00" "00" "00" "00" "00"
[12] "00" "00" "00" "00" "00" "00" "00" "00" "00" "00" "00"
[23] "00" "00" "00" "00" "00" "00" "00" "00" "00" "00" "00"
[34] "00" "00" "00" "00" "00" "00" "00" "00" "00" "00" "00"
[45] "00" "00" "00" "00" "00" "00" "00" "00" "00" "00" "00"
[56] "00" "00" "00" "00" "00" "01" "01" "01" "01" "01" "01"
[67] "01" "01" "01" "01" "01" "01" "01" "01" "01" "01" "01"
[78] "01" "01" "01" "01" "01" "01" "01" "01" "01" "01" "01"
[89] "01" "01" "01" "01" "01" "01" "01" "01" "01" "01" "01"
[100] "01" "01" "01" "01" "01" "01" "01" "01" "01" "01" "01"
[111] "01" "01" "01" "01" "01" "01" "01" "01" "01" "01" "02"
[122] "02" "02" "02" "02" "02" "02" "02" "02" "02" "02" "02"
[133] "02" "02" "02" "02" "02" "02" "02" "02" "02" "02" "02"
[144] "02" "02" "02" "02" "02" "02" "02" "02" "02" "02" "02"
[155] "02" "02" "02" "02" "02" "02" "02" "02" "02" "02" "02"
[166] "02" "02" "02" "02" "02" "02" "02" "02" "02" "02" "02"
[177] "02" "02" "02" "02" "03" "03" "03" "03" "03" "03" "03"
[188] "03" "03" "03" "03" "03" "03" "03" "03" "03" "03" "03"
[199] "03" "03" "03" "03" "03" "03" "03" "03" "03" "03" "03"
[210] "03" "03" "03" "03" "03" "03" "03" "03" "03" "03" "03"
[221] "03" "03" "03" "03" "03" "03" "03" "03" "03" "03" "03"
[232] "03" "03" "03" "03" "03" "03" "03" "03" "03" "04" "04"
[243] "04" "04" "04" "04" "04" "04" "04" "04" "04" "04" "04"
[254] "04" "04" "04" "04" "04" "04" "04" "04" "04" "04" "04"
[265] "04" "04" "04" "04" "04" "04" "04" "04" "04" "04" "04"
[276] "04" "04" "04" "04" "04" "04" "04" "04" "04" "04" "04"
[287] "04" "04" "04" "04" "04" "04" "04" "04" "04" "04" "04"
[298] "04" "04" "04" "05" "05" "05" "05" "05" "05" "05" "05"
[309] "05" "05" "05" "05" "05" "05" "05" "05" "05" "05" "05"
[320] "05" "05" "05" "05" "05" "05" "05" "05" "05" "05" "05"
[331] "05" "05" "05" "05" "05" "05" "05" "05" "05" "05" "05"
[342] "05" "05" "05" "05" "05" "05" "05" "05" "05" "05" "05"
[353] "05" "05" "05" "05" "05" "05" "05" "05" "06" "06" "06"
[364] "06" "06" "06" "06" "06" "06" "06" "06" "06" "06" "06"
[375] "06" "06" "06" "06" "06" "06" "06" "06" "06" "06" "06"
[386] "06" "06" "06" "06" "06" "06" "06" "06" "06" "06" "06"
[397] "06" "06" "06" "06" "06" "06" "06" "06" "06" "06" "06"
[408] "06" "06" "06" "06" "06" "06" "06" "06" "06" "06" "06"
[419] "06" "06" "07" "07" "07" "07" "07" "07" "07" "07" "07"
[430] "07" "07" "07" "07" "07" "07" "07" "07" "07" "07" "07"
[441] "07" "07" "07" "07" "07" "07" "07" "07" "07" "07" "07"
[452] "07" "07" "07" "07" "07" "07" "07" "07" "07" "07" "07"
[463] "07" "07" "07" "07" "07" "07" "07" "07" "07" "07" "07"
[474] "07" "07" "07" "07" "07" "07" "07" "08" "08" "08" "08"
[485] "08" "08" "08" "08" "08" "08" "08" "08" "08" "08" "08"
[496] "08" "08" "08" "08" "08" "08" "08" "08" "08" "08" "08"
[507] "08" "08" "08" "08" "08" "08" "08" "08" "08" "08" "08"
[518] "08" "08" "08" "08" "08" "08" "08" "08" "08" "08" "08"
[529] "08" "08" "08" "08" "08" "08" "08" "08" "08" "08" "08"
[540] "18" "18" "18" "18" "18" "18" "18" "18" "18" "18" "18"
[551] "18" "18" "18" "18" "18" "18" "18" "18" "18" "18" "18"
[562] "18" "18" "18" "18" "18" "18" "18" "18" "18" "18" "18"
[573] "18" "18" "18" "18" "18" "18" "18" "18" "18" "18" "18"
[584] "18" "18" "18" "18" "18" "18" "18" "18" "18" "18" "18"
[595] "18" "18" "18" "18" "18" "19" "19" "19" "19" "19" "19"
[606] "19" "19" "19" "19" "19" "19" "19" "19" "19" "19" "19"
[617] "19" "19" "19" "19" "19" "19" "19" "19" "19" "19" "19"
[628] "19" "19" "19" "19" "19" "19" "19" "19" "19" "19" "19"
[639] "19" "19" "19" "19" "19" "19" "19" "19" "19" "19" "19"
[650] "19" "19" "19" "19" "19" "19" "19" "19" "19" "19" "20"
[661] "20" "20" "20" "20" "20" "20" "20" "20" "20" "20" "20"
[672] "20" "20" "20" "20" "20" "20" "20" "20" "20" "20" "20"
[683] "20" "20" "20" "20" "20" "20" "20" "20" "20" "20" "20"
[694] "20" "20" "20" "20" "20" "20" "20" "20" "20" "20" "20"
[705] "20" "20" "20" "20" "20" "20" "20" "20" "20" "20" "20"
[716] "20" "20" "20" "20" "21" "21" "21" "21" "21" "21" "21"
[727] "21" "21" "21" "21" "21" "21" "21" "21" "21" "21" "21"
[738] "21" "21" "21" "21" "21" "21" "21" "21" "21" "21" "21"
[749] "21" "21" "21" "21" "21" "21" "21" "21" "21" "21" "21"
[760] "21" "21" "21" "21" "21" "21" "21" "21" "21" "21" "21"
[771] "21" "21" "21" "21" "21" "21" "21" "21" "21" "22" "22"
[782] "22" "22" "22" "22" "22" "22" "22" "22" "22" "22" "22"
[793] "22" "22" "22" "22" "22" "22" "22" "22" "22" "22" "22"
[804] "22" "22" "22" "22" "22" "22" "22" "22" "22" "22" "22"
[815] "22" "22" "22" "22" "22" "22" "22" "22" "22" "22" "22"
[826] "22" "22" "22" "22" "22" "22" "22" "22" "22" "22" "22"
[837] "22" "22" "22" "23" "23" "23" "23" "23" "23" "23" "23"
[848] "23" "23" "23" "23" "23" "23" "23" "23" "23" "23" "23"
[859] "23" "23" "23" "23" "23" "23" "23" "23" "23" "23" "23"
[870] "23" "23" "23" "23" "23" "23" "23" "23" "23" "23" "23"
[881] "23" "23" "23" "23" "23" "23" "23" "23" "23" "23" "23"
[892] "23" "23" "23" "23" "23" "23" "00" "00" "00" "00" "00"
[903] "00" "00" "00" "00" "00" "00" "00" "00" "00" "00" "00"
[914] "00" "00" "00" "00" "00" "00" "00" "00" "00" "00" "00"
[925] "00" "00" "00" "00" "00" "00" "00" "00" "00" "00" "00"
[936] "00" "00" "00" "00" "00" "00" "00" "00" "00" "00" "00"
[947] "00" "00" "00" "00" "00" "00" "00" "00" "00" "00" "00"
[958] "01" "01" "01" "01" "01" "01" "01" "01" "01" "01" "01"
[969] "01" "01" "01" "01" "01" "01" "01" "01" "01" "01" "01"
[980] "01" "01" "01" "01" "01" "01" "01" "01" "01" "01" "01"
[991] "01" "01" "01" "01" "01" "01" "01" "01" "01" "01"
[ reached getOption("max.print") -- omitted 23459 entries ]

my aim is to generate another column df$minutes that shows the minutes within each hour. for example if we start following the order I gave it's gonna be

Column A	Column B
0	1
0	2
0	3
.	.
.	.
.	.
1	61
1	62
.	.
.	.
.	.
23	1380
0	1
0	1
0	2
0	3
.	.
.	.
.	.
1	61
1	62
.	.
.	.
.	.
23	1380
0	1

please not 2 things: 1- I don't have the same exact number of minutes in each hours (sometimes it is 60 sometimes it is less) 2- I don't have all hours of the day (there is a gap between 8-18)

I tried this but this is i think suggest that we have the same number of minutes for each hour (which is 60)

`timepf <- as.numeric(df$hours)
n <- length(timepf)

xtime <- numeric()
start <- 1
while (start <= n) {
  end <- min(start + 59, n)
  part <- timepf[start:end]
  xtime_part <- part * 60 + (1:length(part))
  xtime <- c(xtime, xtime_part)
  start <- end + 1
}
xtime
length(xtime)
`

xtime is the minutes column we're looking to create.

Answer 1

I'll demonstrate using much smaller data, just 3 hours a day for only 4 minutes per hour.

df <- data.frame(hour = rep(sprintf("%02i", rep(0:2, each=4)), 3))

Note that my code will assume full 60 minutes, though, so it should work as-is for your data.

The first thing we need to do, though, is account for "day": each time hour increments to "00" from something other than "00" , increment the day. After that, this is simply summarize by group .

dplyr

library(dplyr)
df %>%
  mutate(day = cumsum(hour == "00" & lag(hour != "00", default = FALSE))) %>%
  group_by(day, hour) %>%
  mutate(minute = as.integer(hour) * 60 + row_number()) %>%
  ungroup()
# # A tibble: 36 × 3
#    hour    day minute
#    <chr> <int>  <dbl>
#  1 00        0      1
#  2 00        0      2
#  3 00        0      3
#  4 00        0      4
#  5 01        0     61
#  6 01        0     62
#  7 01        0     63
#  8 01        0     64
#  9 02        0    121
# 10 02        0    122
# # … with 26 more rows
# # ℹ Use `print(n = ...)` to see more rows

Take my word that on day = 1 (the second day) the minute resets to 1 . (Or look in the base-R code below, it's the values.)

base R

df$day <- cumsum(df$hour == "00" & c(FALSE, df$hour[-nrow(df)] != "00"))
df$day <- cumsum(df$hour == "00" & c(FALSE, df$hour[-nrow(df)] != "00"))

I'll note that if you think you may have a day restart lacking any of the "00" hours, you can use an alternate method to determine day by assuming that any decrease in hour means a new day:

df$day2 <- cumsum(diff(as.integer(df$hour)) < 0)

From here, we'll use ave :

df$minute <- ave(as.integer(df$hour), df[c("day","hour")], FUN = function(z) as.integer(z) * 60 + seq_along(z))
df
#    hour day minute
# 1    00   0      1
# 2    00   0      2
# 3    00   0      3
# 4    00   0      4
# 5    01   0     61
# 6    01   0     62
# 7    01   0     63
# 8    01   0     64
# 9    02   0    121
# 10   02   0    122
# 11   02   0    123
# 12   02   0    124
# 13   00   1      1
# 14   00   1      2
# 15   00   1      3
# 16   00   1      4
# 17   01   1     61
# 18   01   1     62
# 19   01   1     63
# 20   01   1     64
# 21   02   1    121
# 22   02   1    122
# 23   02   1    123
# 24   02   1    124
# 25   00   2      1
# 26   00   2      2
# 27   00   2      3
# 28   00   2      4
# 29   01   2     61
# 30   01   2     62
# 31   01   2     63
# 32   01   2     64
# 33   02   2    121
# 34   02   2    122
# 35   02   2    123
# 36   02   2    124