Version 1.3.0 ------------------------------------------------------------------------- DEVELOPMENT * v1.3.0. treats math with month and year Periods more consistently. If adding or subtracting n months would result in a non-existent date, lubridate will return an NA instead of a day in the following month or year. For example, `ymd("2013-01-31") + months(1)` will return `NA` instead of `2013-03-04` as in v1.2.0. `ymd("2012-02-29") + years(1)` will also return an `NA`. This rule change helps ensure that date + timespan - timespan = date (or NA). If you'd prefer that such arithmetic just returns the last day of the resulting month, see `%m+%` and `%m-%`. * update.POSIXct and update.POSIXlt have been rewritten to be 7x faster than their versions in v1.2.0. The speed gain is felt in `force_tz`, `with_tz`, `floor_date`, `ceiling_date`, `second<-`, `minute<-`, `hour<-`, `day<-`, `month<-`, `year<-`, and other functions that rely on update (such as math with Periods). * lubridate includes a Korean translation provided by http://korea.gnu.org/gnustats/ NEW FEATURES * lubridate parser and stamp functions now handle ISO8601 date format (e.g., 2013-01-24 19:39:07.880-06:00, 2013-01-24 19:39:07.880Z) * lubridate v1.3.0 comes with a new R vignette. see `browseVignettes("lubridate")` to view it. * The accessors `second`, `minute`, `hour`, `day`, `month`, `year` and the settors `second<-`, `minute<-`, `hour<-`, `day<-`, `month<-`, `year<-` now work on Period class objects * users can control which messages lubridate returns when parsing and estimating with the global option lubridate.verbose. Run `options(lubridate.verbose = TRUE)` to turn parsing messages on. Run `options(lubridate.verbose = FALSE)` to turn estimation and coercion messages off. * lubridate parser functions now propagate NA's just as as.POSIXct, strptime and other functions do. Previously lubridate's parse functions would only return an error. * added [[ and [[<- methods for INterval, Period and Duration class objects * added `%m+%` and `%m-%` methods for Interval and Duration class objects that throw useful errors. * `olson_time_zones` retreives a character vector is Olson-style time zone names to use in lubridate * summary methods for Interval, Period, and Duration classes * date_decimal converts a date written as a decimal of a year into a POSIXct date-time BUG FIXES * fixed bug in way update.POSIXct and update.POSIXlt handle dates that occur in the fall daylight savings overlap. update will choose the date-time closest to the original date time (on the timeline) when two identical clock times exist due to the DST overlap. * fixed bugs that created unintuitive results for `as.interval`, `int_overlaps`, `%within%` and the interval methods of `c`, `intersect`, `union`, `setdiff`, and `summary`. * parse functions, `as.interval`, `as.period` and `as.duration` now handle vectors of NA's without returning errors. * parsers better handle vectors of input that have more than 100 elements and many NAs * data frames that contain timespan objects with NAs in thme no longer fail to print * `round_date`, `ceiling_date` and `update` now correctly handle input of length zero * `decimal_date` no longer returns NaN for first second of the year Version 1.2.0 ------------------------------------------------------------------------- DEVELOPMENT * lubridate 1.2.0 is significantly faster than lubridate 1.1.0. This is largely thanks to a parser rewrite submitted by Vitalie Spinu. Thank you, Vitalie. Some metrics: - parser speed up - 60x faster - `with_tz` speed up - 15x faster - `force_tz` speed up - 3x faster * Development for 1.2.0 has also focused on improving the way we work with months. `rollback` rolls dates back to the last day of the previous month. provides more options for working with months. `days_in_month` finds the number of days in a date's month. And, `%m+%` and `%m-%` provide a new way to handle unequal month lengths while doing arithmetic. See NEW FEATURES for more details * date parsing can now parse multiple date formats within the same vector of date-times. Parsing can also recognize a greater variety of date-time formats as well as incomplete (truncated) date-times. Contributed by Vitalie Spinu. Thank you, Vitalie. * 1.2.0 introduces a new display format for periods. The display is more math and international friendly. * 1.2.0 transforms negative intervals into periods much more gracefully (e.g, - 3 days instead of -1 years, 11 months, and 27 days) * S3 update methods are now exported NEW FEATURES * `stamp` allows users to print dates in whatever form they like. Contributed by Vitalie Spinu. Thank you, Vitalie. * periods now handle fractional seconds. Contributed by Vitalie Spinu. Thank you, Vitalie. * date parsing can now parse multiple date formats within the same vector of date-times. Parsing can also recognize a greater variety of date-time formats as well as incomplete (truncated) date-times. Contributed by Vitalie Spinu. Thank you, Vitalie. * `sort`, `order`, `rank` and `xtfrm` now work with periods * `as.period.Interval` accepts a unit argument. `as.period` will convert intervals into periods no larger than the supplied unit. * `days_in_month` takes a date, returns the number of days in the date's month. Contributed by Richard Cotton. Thank you, Richard. * `%m+%` and `%m-%` perform addition and subtraction with months (and years) without rollover at the end of a month. These can be used in place of + and -. These can't be used with periods smaller than a month, which should be handled separately. An example of the new behavior: ymd("2010-01-31") %m+% months(1) # "2010-02-28 UTC" ymd("2010-01-31") + months(1) # "2010-03-03 UTC" ymd("2010-03-31") %m-% months(1) # "2010-02-28 UTC" ymd("2010-01-31") - months(1) # "2010-03-03 UTC" * `rollback` rolls a date back to the last day of the previous month. * `quarter` returns the fiscal quarter that a date occurs in. Like `quartes` in base R, but returns a numeric instead of a character string. BUG FIXES * date parsers now handle NAs * periods now handle NAs * `[<-` now correctly updates all elements of a period inside a vector, list, or data.frame * `period()` now works with unit = "weeks" * `ceiling_date` no longer rounds up if a date is already at a ceiling * the redundant (i.e, repeated) hour of fall daylight savings time now displays with the correct time zone * `update.POSIXct` and `update.POSIXlt` handle vectors that sum to zero in the days argument * the format method for periods, intervals and duration now accurately displays objects of length 0. Version 1.1.0 ------------------------------------------------------------------------- DEVELOPMENT * lubridate no longer overwrites base R methods for +, - , *, /, %%, and %/%. To recreate the previous experience of subtracting two date times to create an interval, we've added the interval creation function %--%. * lubridate has moved to an S4 object system. Timespans, Intervals, Durations, and Periods have each been redefined as an S4 class with its own methods. * arithmetic operations will no longer perform implicit class changes between timespans. Users must explicitly state how and when they wish class changes to occur with as.period(), as.duration(), and as.interval(). This makes code written with lubridate more robust, as such implicit changes often did not produce consistent behavior across a variety of operations. It also allows lubridate to be less chatty with fewer console messages. lubridate does not need to explain what it is doing, because it no longer attempts to do things whose outcome would not be clear. On the other hand, arithmetic between multiple time classes will produce informative error messages. * the internal structure of lubridate R code has been reorganized at https://github.com/hadley/lubridate to make lubridate more development friendly. NEW FEATURES * intervals are now more useful and lubridate has more ways to manipulate them. Intervals can be created with %--%; modified with int_shift(), int_flip(), and int_standardize(); manipulated with intersect(), union(), and setdiff(); and used in logical tests with int_aligns(), int_overlaps(), and %within%. lubridate will no longer perform arithmetic between two intervals because the correct results of such operations is no more obvious than the correct result of adding two dates. Instead users are encouraged to use the new set operations or to directly modify intervals with int_start() and int_end(), which can also be used as settors. lubridate now supports negative intervals as well as positive intervals. Intervals also now display with a time zone. * Modulo methods for timespans have been changed to return a timespan. this allows modulo methods to be used with integer division in an intuitive manner, e.g. a = a %/% b * b + a %% b Users can still acheive a numerical result by using as.numeric() on input before performing modulo. * Periods, durations, and intervals can now all be put into a data frame. * Periods, durations, and intervals can be intuitively subset with $ and []. These operations also can be used as settors with <-. * The parsing functions and the as.period method for intervals are now slightly faster. * month<- and wday<- settors accept names as well as numbers * parsing functions now have a quiet argument to parse without messages and a tz argument to directly parse times into the desired time zone. * logical comparison methods now work for period objects. Version 0.2.6 ------------------------------------------------------------------------- * use `test_package` to avoid incompatibility with current version of `testthat` * other minor fixes to pass `R CMD check` Version 0.2.5 ------------------------------------------------------------------------- * added ymdThms() for parsing ISO 8061 formatted combned dates and times BUG FIXES * removed bug in parsing dates with "T" in them * modified as.period.interval() to display periods in positive units Version 0.2.4 ------------------------------------------------------------------------- * Add citations to JSS article Version 0.2.3 ------------------------------------------------------------------------- NEW FEATURES * ymd_hms(), hms(), and ms() functions can now parse dates that include decimal values in the seconds element. * milliseconds(), microseconds(), nanoseconds(), and picoseconds() create period objects of the specified lengths. dmilliseconds(), dmicroseconds(), dnanoseconds(), and dpicoseconds() make duration objects of the specified lengths. BUG FIXES * lubridate no longer overwrites months(), start(), and end() from base R. Start and end have been replaced with int_start() and int_end(). * lubridate imports plyr and stringr packages, instead of depending on them. Version 0.2.2 ------------------------------------------------------------------------- NEW FEATURES * made division, modulo, and integer division operations compatible with difftimes * created c() methods for periods and durations BUG FIXES * fixed bug in division, modulo, and integer operations with timespans Version 0.2.1 ------------------------------------------------------------------------- NEW FEATURES * created parsing functions ymd_hm ymd_h dmy_hms dmy_hm dmy_h mdy_hms mdy_hm mdy_h ydm_hms ydm_hm ydm_h, which operate in the same way as ymd_hms(). BUG FIXES * fixed bug in add_dates(). duration objects can now be successfully added to numeric objects. Version 0.2 ------------------------------------------------------------------------- NEW FEATURES * division between timespans: each timespan class (durations, periods, intervals) can be divided by other timespans. For example, how many weeks are there between Halloween and Christmas?: (christmas - halloween) / weeks(1) * modulo operations between timespans * duration objects now have their own class and display format separate from difftimes * interval objects now use an improved data structure and have a cleaner display format * lubridate now loads its own namespace * math operations now automatically coerce interval objects to duration objects. Allows intervals to be used "right out of the box" without error messages. * created start() and end() functions for accessing and changing the boundary date-times of an interval * rep() methods for periods, intervals, and durations MINOR CHANGES * added a package help page with functions listed by purpose * eseconds(), eminutes(), etc. are aliased to dseconds(), dminutes(), etc. to make it easier to remember they are duration objects. * changed leap.years() to leap_years() to maintain consistent naming scheme BUG FIXES * rewrote as.period() to create only positive periods. * fixed rollover bug in update.POSIXct() * edited make_diff() to display in days when approporiate, not weeks