CODEWITHSUNDEEP
rlubridate
Ani
Ani

Reputation: 323

Duration in seconds since midnight on specific day

Say I have a start date and time "2016-01-09 15:23:26" and measurements taken at varying intervals with the date and time recorded for each measurement.

Sample data follow:

date           time         date_time            clock
"2016-01-09"   "15:23:26"   2016-01-09 15:23:2   0s (0 seconds)      
"2016-01-10"   "23:59:53"   2016-01-09 23:59:53  30987s (~8.61 hours)
"2016-01-10"   "00:04:53"   NA                   NA
"2016-01-10"   "01:04:55"   2016-01-10 01:04:55  34889s (~9.69 hours)

If I try to use lubridate to calculate the duration, in minutes since the start time, the calculation works fine for all but row 3 (where the date is "2016-01-10" and the time is "00:04:53". I've tried to look on the web for some possible explanation for what is going wrong here but to no avail. What am I missing? My code follows:

library(lubridate)
df$date2 = mdy(df$Date)
df$time2 = hms(df$Time)
df$date_time = paste(df$date2, df$time2, sep = " ")
df$date_time = ymd_hms(df$date_time)
df$start_time = ymd_hms("2016-01-09 15:23:26", tz="UTC")
df$clock = as.duration(df$date_time - df$start_time)

Upvotes: 1

Views: 923

Answers (1)

HubertL
HubertL

Reputation: 19544

When you paste date and time, because third time is less than an hour, it is not recognized by ymd_hms()

Since you already have POSIXct objects, you can sum them directly.

Simply replace :

df$date_time = paste(df$date2, df$time2, sep = " ")
df$date_time = ymd_hms(df$date_time)

by:

df$date_time = df$date2+df$time2

Upvotes: 1

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