> data <- c("2016-03-15 13","2016-03-16 23","2016-03-17 06","2016-03-18 15","2016-03-19 08","2016-03-20 21")
> datevec <- strptime(data,"%Y-%m-%d %H")
> difftime(datevec[-length(datevec)],datevec[-1],units="hours")