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I would like to get the duration of two variables. I would like the result to in hr : min : sec format. Here is my code.

Total_Trips$Trip_Duration <- as.POSIXct(Total_Trips$started_at - Total_Trips$ended_at, format = "%H:%M:%S")

Here is the df info and the error.

'data.frame':   4558885 obs. of  13 variables:
 $ ride_id           : chr  "A847FADBBC638E45" "5405B80E996FF60D" "5DD24A79A4E006F4" "2A59BBDF5CDBA725" ...
 $ rideable_type     : chr  "docked_bike" "docked_bike" "docked_bike" "docked_bike" ...
 $ started_at        : POSIXct, format: "2020-04-26 17:45:14" "2020-04-17 17:08:54" "2020-04-01 17:54:13" "2020-04-07 12:50:19" ...
 $ ended_at          : POSIXct, format: "2020-04-26 18:12:03" "2020-04-17 17:17:03" "2020-04-01 18:08:36" "2020-04-07 13:02:31" ...
 $ start_station_name: chr  "Eckhart Park" "Drake Ave & Fullerton Ave" "McClurg Ct & Erie St" "California Ave & Division St" ...
 $ start_station_id  : chr  "86" "503" "142" "216" ...
 $ end_station_name  : chr  "Lincoln Ave & Diversey Pkwy" "Kosciuszko Park" "Indiana Ave & Roosevelt Rd" "Wood St & Augusta Blvd" ...
 $ end_station_id    : chr  "152" "499" "255" "657" ...
 $ start_lat         : num  41.9 41.9 41.9 41.9 41.9 ...
 $ start_lng         : num  -87.7 -87.7 -87.6 -87.7 -87.6 ...
 $ end_lat           : num  41.9 41.9 41.9 41.9 42 ...
 $ end_lng           : num  -87.7 -87.7 -87.6 -87.7 -87.7 ...
 $ member_casual     : chr  "member" "member" "member" "member" ...

> Total_Trips$Trip_Duration <- as.POSIXct(Total_Trips$started_at - Total_Trips$ended_at, format = "%H:%M:%S")

Error in as.POSIXct.default(Total_Trips$started_at - Total_Trips$ended_at, : do not know how to convert 'Total_Trips$started_at - Total_Trips$ended_at' to class “POSIXct”

Vinícius Félix
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mackartist
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  • In R, a `POSIXt` object is a date/time, not a time-difference. See https://stackoverflow.com/q/19721145/3358272 and https://stackoverflow.com/a/69137009/3358272 for some options. If you need `Trip_Duration` to remain "number-like" where you can use arithmetic on it, then you need to keep it as `numeric` (controlling its units), preserving the conversion to `HH:MM:SS` until you need to render a report/table. – r2evans Oct 04 '21 at 20:49

1 Answers1

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Please find below one solution with the lubridate package:

REPREX:

library(lubridate)
 
started_at <- as_datetime(c("2020-04-26 17:45:14", "2020-04-17 17:08:54", "2020-04-01 17:54:13", "2020-04-07 12:50:19"))
ended_at <- as_datetime(c("2020-04-26 18:12:03", "2020-04-17 17:17:03", "2020-04-01 18:08:36", "2020-04-07 13:02:31"))
(results <- hms::as_hms(ended_at - started_at))
#> 00:26:49
#> 00:08:09
#> 00:14:23
#> 00:12:12

Created on 2021-10-04 by the reprex package (v2.0.1)

If you want to apply this solution to your dataframe, you should write something like this (after installing and loading the lubridate library):

Total_Trips$Trip_Duration <- hms::as_hms(as_datetime(Total_Trips$ended_at) - as_datetime(Total_Trips$started_at))

lovalery
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  • I tried that and I got this. Error in as_datetime(Total_Trips$ended_at) : could not find function "as_datetime" – mackartist Oct 05 '21 at 02:41
  • Hi @ mackartist, I assume you are getting this error message because the `lubridate` package is not installed and/or loaded in your machine. You need to first (i) install the package with the line of code `install.packages("lubridate")` , then (ii) load the library with the line of code `library(lubridate)` , and only then run the line of code I gave in my answer above. Let me know if it's O.K. If it is, please mark this answer as accepted to make it easier for other users to find the right answers. If not, please write what the problem still is. Cheers. – lovalery Oct 05 '21 at 08:37