How to convert time to decimal

Question

I have a large data set containing time in hh:mm:ss format and I would like to convert these to a decimal format while ignoring the hours (hh). I have used strptime but this

Answer 1

There is probably a lubridate function for this, but I'd do it like this:

x <-  "01:18:30"

y <- (as.numeric(as.POSIXct(paste("2014-01-01", x))) - 
   as.numeric(as.POSIXct("2014-01-01 0:0:0")))/60
#[1] 78.5

Ignoring the hours:

y%%60
#[1] 18.5