How to Parse Year + Week Number in R?

by

This is kinda like another question you may have seen before. 🙂

The key issue is: what day should a week number specify? Is it the first day of the week? The last? That’s ambiguous. I don’t know if week one is the first day of the year or the 7th day of the year, or possibly the first Sunday or Monday of the year (which is a frequent interpretation). (And it’s worse than that: these generally appear to be 0-indexed, rather than 1-indexed.) So, an enumerated day of the week needs to be specified.

For instance, try this:

as.POSIXlt("2008 42 1", format = "%Y %U %u")

The %u indicator specifies the day of the week.

Additional note: See ?strptime for the various options for format conversion. It’s important to be careful about the enumeration of weeks, as these can be split across the end of the year, and day 1 is ambiguous: is it specified based on a Sunday or Monday, or from the first day of the year? This should all be specified and tested on the different systems where the R code will run. I’m not certain that Windows and POSIX systems sing the same tune on some of these conversions, hence I’d test and test again.

More Related Contents:

  1. How to prevent ifelse() from turning Date objects into numeric objects
  2. strptime, as.POSIXct and as.Date return unexpected NA
  3. How to flatten / merge overlapping time periods
  4. Split date-time column into Date and time variables
  5. efficiently generate a random sample of times and dates between two dates
  6. Change timezone in a POSIXct object
  7. How to parse milliseconds?
  8. How do you convert POSIX date to day of year?
  9. Split time series data into time intervals (say an hour) and then plot the count
  10. calculating time difference in R
  11. Date conversion from POSIXct to Date in R
  12. Convert seconds to days: hours:minutes:seconds
  13. Understanding dates and plotting a histogram with ggplot2 in R
  14. How to join two dataframes by nearest time-date?
  15. How to determine if date is a weekend or not (not using lubridate)
  16. Rounding time to nearest quarter hour
  17. Change day of the month in a Date to first day (01)
  18. Handling dates when we switch to daylight savings time and back
  19. Checking if Date is Between two Dates in R
  20. extract hours and seconds from POSIXct for plotting purposes in R
  21. Convert hours:minutes:seconds to minutes
  22. R: merge two irregular time series
  23. Calculating Time Difference between two columns
  24. Converting numeric time to datetime POSIXct format in R
  25. R: convert date from character to datetime [duplicate]
  26. as.Date(as.POSIXct()) gives the wrong date?
  27. Convert decimal day to HH:MM
  28. R datetime series missing values
  29. Round a POSIX date (POSIXct) with base R functionality
  30. How to calculate time difference with previous row of a data.frame by group

Leave a Comment