CODEWITHSUNDEEP
rlubridate
boshek
boshek

Reputation: 4416

Date objects in decimals spanning multiple leap years

I would like to figure out a way to convert a day into a decimal where 0 is January 1 and December 31 is 1. No time here just days. I looked for a few solutions like here and here but neither of those solution seem to fit my problem. I also had hopes for the date_decimal function in lubridate. I have figured out a solution which involves converting the Date into a number, merging a dataframe that accounts for leaps years then divides the number by the total number of days in the year. 

library(lubridate)
library(dplyr)

 df <- data.frame(Date=seq(as.Date("2003/2/10"), as.Date("2007/2/10"), "years"),
       var=seq(1,5, by=1))

lubridate function attempt:

 date_decimal(df$Date)

Leap year dataframe

 maxdaydf<-data.frame(Year=seq(2003,2007,by=1),   maxdays=c(365,366,365,365,365))

A dplyr pipe to generate the daydecimal:

df %>%
  mutate(Year=year(Date), daynum=yday(Date)) %>%
  full_join(maxdaydf, by=c("Year")) %>%
  mutate(daydecimal=daynum/maxdays)

But as I said this is clunky and involves a 2nd dataframe which is never ideal. Any suggestions on how I can convert some Dates into decimals?

Upvotes: 0

Views: 131

Answers (1)

HubertL
HubertL

Reputation: 19544

Instead of date_decimal() you could use decimal_date()

decimal_date(df$Date)
[1] 2003.110 2004.109 2005.110 2006.110 2007.110

Or you can use :

yday(df$Date)/yday(ISOdate(year(df$Date), 12,31))
[1] 0.1123288 0.1120219 0.1123288 0.1123288 0.1123288

Upvotes: 2

Related Questions