I am trying to make a function that converts time (in character form) to decimal format such that 1 corresponds to 1 am and 23 corresponds to 11 pm and 24 means the end of the day.
Here are the two function that does this. Here one function vectorizes while other do
time2dec <- function(time0)
{
time.dec <-as.numeric(substr(time0,1,2))+as.numeric(substr(time0,4,5))/60+(as.numeric(substr(time0,7,8)))/3600
return(time.dec)
}
time2dec1 <- function(time0)
{
time.dec <-as.numeric(strsplit(time0,':')[[1]][1])+as.numeric(strsplit(time0,':')[[1]][2])/60+as.numeric(strsplit(time0,':')[[1]][3])/3600
return(time.dec)
}
This is what I get...
times <- c('12:23:12','10:23:45','9:08:10')
#>time2dec(times)
[1] 12.38667 10.39583 NA
Warning messages:
1: In time2dec(times) : NAs introduced by coercion
2: In time2dec(times) : NAs introduced by coercion
#>time2dec1(times)
[1] 12.38667
I know time2dec which is vectorized, gives NA for the last element because it extracts 9: instead of 9 as hour. That is why I created time2dec1 but I do not know why it is not getting vectorized.
I will also be interested in getting a better function for doing what I am trying to do. I saw this which explain a part of my question but does not provide a clue to do what I am trying.
Don't try to reinvent the wheel:
times1 <- difftime(as.POSIXct(times, "%H:%M:%S", tz="GMT"),
as.POSIXct("0:0:0", "%H:%M:%S", tz="GMT"),
units="hours")
#Time differences in hours
#[1] 12.386667 10.395833 9.136111
as.numeric(times1)
#[1] 12.386667 10.395833 9.136111