CODEWITHSUNDEEP
rdatetimeintegerdatetime-conversion
ksaittis
ksaittis

Reputation: 51

Convert Integers to Time and Make Calculations in R

I’m having difficulties with a date time problem. My data frame looks like this and I want to find the duration that each person watches TV.

Start.Time <- c(193221,201231,152324,182243,123432,192245)
End.Time <- c(202013,211232,154521,183422,133121,201513)
cbind(Start.Time,End.Time)

I have tried different methods to convert them in order to be able to make calculation but I didn’t produce any significant results.

as.POSIXct(Start.Time , origin="2015-11-01")

My results are completely wrong

[1] "2015-11-03 05:40:21 GMT" "2015-11-03 07:53:51 GMT"
[3] "2015-11-02 18:18:44 GMT" "2015-11-03 02:37:23 GMT"
[5] "2015-11-02 10:17:12 GMT" "2015-11-03 05:24:05 GMT"

For example I want 193221 to become 19:32:21 HH:MM:SS

Is there a package out there that easily does the conversion? and if its possible i don't want the date displayed, just the time.

Upvotes: 2

Views: 248

Answers (1)

Stibu
Stibu

Reputation: 15897

You can convert your numbers to actual time stamps (in POSIXct format) like this:

Start.Time <- c(193221,201231,152324,182243,123432,192245)
Start.POSIX <- as.POSIXct(as.character(Start.Time), format = "%H%M%S")
Start.POSIX
## [1] "2015-12-19 19:32:21 CET" "2015-12-19 20:12:31 CET" "2015-12-19 15:23:24 CET"
## [4] "2015-12-19 18:22:43 CET" "2015-12-19 12:34:32 CET" "2015-12-19 19:22:45 CET"

As you can see, as.POSIXct assumes the times to belong to the current date. POSIXct alway denotes a specific moment in time and thus contains not only a time but also a date. You can now easily do calculations with these:

End.Time <- c(202013,211232,154521,183422,133121,201513)
End.POSIX <- as.POSIXct(as.character(End.Time), format = "%H%M%S")
End.POSIX - Start.POSIX
## Time differences in mins
## [1] 47.86667 60.01667 21.95000 11.65000 56.81667 52.46667

When you print the POSIXct objects (as I did above with Start.POSIX) they are acutally converted to characters and these are printed. You can see this, because there are " around the dates. You can control the format that is used when printing and thus, you could print the times only as follows:

format(Start.POSIX, "%H:%M:%S")
## [1] "19:32:21" "20:12:31" "15:23:24" "18:22:43" "12:34:32" "19:22:45"

Upvotes: 1

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