Changing date-time format without loosing duration

General
1

Hi Team

I collected some data (see attached) using kobotool box platform, while mutating the start variable which is a date and time variable that came in as character to date. I noticed that the time changed significantly. I used the ymd_hms() function.

See below output for the first 6 observation. Start time before applying the ymd_hms() function is 08:44:52, then, 08:52:52, 09:02:09 .....
After mutating 05:44:52, 05:52:52, 09:02:09 .....
What could be the problem?
datetime_data.pdf (21.9 KB)

Before Mutating
start
1 2025-02-25T08:44:52.976+03:00
2 2025-02-25T08:52:52.535+03:00
3 2025-02-25T09:02:09.595+03:00
4 2025-02-25T09:02:54.823+03:00
5 2025-02-25T09:11:27.205+03:00
6 2025-02-25T09:03:27.331+03:00

After Mutating
trio %>% #Two

  • mutate(
  • start = ymd_hms(start)

  • ) %>%
  • select(start) %>%
  • head()
    start
    1 2025-02-25 05:44:52
    2 2025-02-25 05:52:52
    3 2025-02-25 06:02:09
    4 2025-02-25 06:02:54
    5 2025-02-25 06:11:27
    6 2025-02-25 06:03:27
2

Looking at the help for ymd_hms(), it defaults to using the UTC time zone. Your times have been shifted by three hours because they were marked as being from the +03:00 time zone. You can use the tzparameter of ymd_hms() to assign a time zone, or just work in UTC.

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