# date and datetime class - Tadayoshi Funaba 1998-2011 # # 'date' provides two classes: Date and DateTime. # # ## Terms and Definitions # # Some terms and definitions are based on ISO 8601 and JIS X 0301. # # ### Calendar Date # # The calendar date is a particular day of a calendar year, identified by its # ordinal number within a calendar month within that year. # # In those classes, this is so-called "civil". # # ### Ordinal Date # # The ordinal date is a particular day of a calendar year identified by its # ordinal number within the year. # # In those classes, this is so-called "ordinal". # # ### Week Date # # The week date is a date identified by calendar week and day numbers. # # The calendar week is a seven day period within a calendar year, starting on a # Monday and identified by its ordinal number within the year; the first # calendar week of the year is the one that includes the first Thursday of that # year. In the Gregorian calendar, this is equivalent to the week which includes # January 4. # # In those classes, this is so-called "commercial". # # ### Julian Day Number # # The Julian day number is in elapsed days since noon (Greenwich Mean Time) on # January 1, 4713 BCE (in the Julian calendar). # # In this document, the astronomical Julian day number is the same as the # original Julian day number. And the chronological Julian day number is a # variation of the Julian day number. Its days begin at midnight on local time. # # In this document, when the term "Julian day number" simply appears, it just # refers to "chronological Julian day number", not the original. # # In those classes, those are so-called "ajd" and "jd". # # ### Modified Julian Day Number # # The modified Julian day number is in elapsed days since midnight (Coordinated # Universal Time) on November 17, 1858 CE (in the Gregorian calendar). # # In this document, the astronomical modified Julian day number is the same as # the original modified Julian day number. And the chronological modified Julian # day number is a variation of the modified Julian day number. Its days begin at # midnight on local time. # # In this document, when the term "modified Julian day number" simply appears, # it just refers to "chronological modified Julian day number", not the # original. # # In those classes, those are so-called "amjd" and "mjd". # # ## Date # # A subclass of Object that includes the Comparable module and easily handles # date. # # A Date object is created with Date::new, Date::jd, Date::ordinal, # Date::commercial, Date::parse, Date::strptime, Date::today, Time#to_date, etc. # # require 'date' # # Date.new(2001,2,3) # #=> # # Date.jd(2451944) # #=> # # Date.ordinal(2001,34) # #=> # # Date.commercial(2001,5,6) # #=> # # Date.parse('2001-02-03') # #=> # # Date.strptime('03-02-2001', '%d-%m-%Y') # #=> # # Time.new(2001,2,3).to_date # #=> # # # All date objects are immutable; hence cannot modify themselves. # # The concept of a date object can be represented as a tuple of the day count, # the offset and the day of calendar reform. # # The day count denotes the absolute position of a temporal dimension. The # offset is relative adjustment, which determines decoded local time with the # day count. The day of calendar reform denotes the start day of the new style. # The old style of the West is the Julian calendar which was adopted by Caesar. # The new style is the Gregorian calendar, which is the current civil calendar # of many countries. # # The day count is virtually the astronomical Julian day number. The offset in # this class is usually zero, and cannot be specified directly. # # A Date object can be created with an optional argument, the day of calendar # reform as a Julian day number, which should be 2298874 to 2426355 or # negative/positive infinity. The default value is `Date::ITALY` # (2299161=1582-10-15). See also sample/cal.rb. # # $ ruby sample/cal.rb -c it 10 1582 # October 1582 # S M Tu W Th F S # 1 2 3 4 15 16 # 17 18 19 20 21 22 23 # 24 25 26 27 28 29 30 # 31 # # $ ruby sample/cal.rb -c gb 9 1752 # September 1752 # S M Tu W Th F S # 1 2 14 15 16 # 17 18 19 20 21 22 23 # 24 25 26 27 28 29 30 # # A Date object has various methods. See each reference. # # d = Date.parse('3rd Feb 2001') # #=> # # d.year #=> 2001 # d.mon #=> 2 # d.mday #=> 3 # d.wday #=> 6 # d += 1 #=> # # d.strftime('%a %d %b %Y') #=> "Sun 04 Feb 2001" # class Date # Creates a date object denoting the given calendar date. # # In this class, BCE years are counted astronomically. Thus, the year before # the year 1 is the year zero, and the year preceding the year zero is the year # -1. The month and the day of month should be a negative or a positive number # (as a relative month/day from the end of year/month when negative). They # should not be zero. # # The last argument should be a Julian day number which denotes the day of # calendar reform. Date::ITALY (2299161=1582-10-15), Date::ENGLAND # (2361222=1752-09-14), Date::GREGORIAN (the proleptic Gregorian calendar) and # Date::JULIAN (the proleptic Julian calendar) can be specified as a day of # calendar reform. # # Date.new(2001) #=> # # Date.new(2001,2,3) #=> # # Date.new(2001,2,-1) #=> # # # See also ::jd. # def initialize: (?Integer year, ?Integer month, ?Integer mday, ?Integer start) -> void include Comparable # Returns a hash of parsed elements. # def self._httpdate: (String str) -> Hash[Symbol, Integer] # Returns a hash of parsed elements. # def self._iso8601: (String str) -> Hash[Symbol, Integer] # Returns a hash of parsed elements. # def self._jisx0301: (String str) -> Hash[Symbol, Integer] # Parses the given representation of date and time, and returns a hash of parsed # elements. This method does not function as a validator. # # If the optional second argument is true and the detected year is in the range # "00" to "99", considers the year a 2-digit form and makes it full. # # Date._parse('2001-02-03') #=> {:year=>2001, :mon=>2, :mday=>3} # def self._parse: (String str, ?boolish complete) -> Hash[Symbol, Integer] # Returns a hash of parsed elements. # def self._rfc2822: (String str) -> Hash[Symbol, Integer | String] # Returns a hash of parsed elements. # def self._rfc3339: (String str) -> Hash[Symbol, Integer | String] # Returns a hash of parsed elements. # def self._rfc822: (String str) -> Hash[Symbol, Integer | String] # Parses the given representation of date and time with the given template, and # returns a hash of parsed elements. _strptime does not support specification # of flags and width unlike strftime. # # Date._strptime('2001-02-03', '%Y-%m-%d') # #=> {:year=>2001, :mon=>2, :mday=>3} # # See also strptime(3) and #strftime. # def self._strptime: (String str, ?String format) -> Hash[Symbol, Integer] # Returns a hash of parsed elements. # def self._xmlschema: (String str) -> Hash[Symbol, Integer] # Creates a date object denoting the given calendar date. # # In this class, BCE years are counted astronomically. Thus, the year before # the year 1 is the year zero, and the year preceding the year zero is the year # -1. The month and the day of month should be a negative or a positive number # (as a relative month/day from the end of year/month when negative). They # should not be zero. # # The last argument should be a Julian day number which denotes the day of # calendar reform. Date::ITALY (2299161=1582-10-15), Date::ENGLAND # (2361222=1752-09-14), Date::GREGORIAN (the proleptic Gregorian calendar) and # Date::JULIAN (the proleptic Julian calendar) can be specified as a day of # calendar reform. # # Date.new(2001) #=> # # Date.new(2001,2,3) #=> # # Date.new(2001,2,-1) #=> # # # See also ::jd. # def self.civil: (?Integer year, ?Integer month, ?Integer mday, ?Integer start) -> Date # Creates a date object denoting the given week date. # # The week and the day of week should be a negative or a positive number (as a # relative week/day from the end of year/week when negative). They should not # be zero. # # Date.commercial(2001) #=> # # Date.commercial(2002) #=> # # Date.commercial(2001,5,6) #=> # # # See also ::jd and ::new. # def self.commercial: (?Integer cwyear, ?Integer cweek, ?Integer cwday, ?Integer start) -> Date # Returns true if the given year is a leap year of the proleptic Gregorian # calendar. # # Date.gregorian_leap?(1900) #=> false # Date.gregorian_leap?(2000) #=> true # def self.gregorian_leap?: (Integer year) -> bool # Creates a new Date object by parsing from a string according to some RFC 2616 # format. # # Date.httpdate('Sat, 03 Feb 2001 00:00:00 GMT') # #=> # # def self.httpdate: (String str, ?Integer start) -> Date # Creates a new Date object by parsing from a string according to some typical # ISO 8601 formats. # # Date.iso8601('2001-02-03') #=> # # Date.iso8601('20010203') #=> # # Date.iso8601('2001-W05-6') #=> # # def self.iso8601: (String str, ?Integer start) -> Date # Creates a date object denoting the given chronological Julian day number. # # Date.jd(2451944) #=> # # Date.jd(2451945) #=> # # Date.jd(0) #=> # # # See also ::new. # def self.jd: (Integer jd, ?Integer start) -> Date # Creates a new Date object by parsing from a string according to some typical # JIS X 0301 formats. # # Date.jisx0301('H13.02.03') #=> # # # For no-era year, legacy format, Heisei is assumed. # # Date.jisx0301('13.02.03') #=> # # def self.jisx0301: (String str, ?Integer start) -> Date # Returns true if the given year is a leap year of the proleptic Julian # calendar. # # Date.julian_leap?(1900) #=> true # Date.julian_leap?(1901) #=> false # def self.julian_leap?: (Integer year) -> bool # Returns true if the given year is a leap year of the proleptic Gregorian # calendar. # # Date.gregorian_leap?(1900) #=> false # Date.gregorian_leap?(2000) #=> true # def self.leap?: (Integer year) -> bool # Creates a date object denoting the given ordinal date. # # The day of year should be a negative or a positive number (as a relative day # from the end of year when negative). It should not be zero. # # Date.ordinal(2001) #=> # # Date.ordinal(2001,34) #=> # # Date.ordinal(2001,-1) #=> # # # See also ::jd and ::new. # def self.ordinal: (?Integer year, ?Integer yday, ?Integer start) -> Date # Parses the given representation of date and time, and creates a date object. # This method does not function as a validator. # # If the optional second argument is true and the detected year is in the range # "00" to "99", considers the year a 2-digit form and makes it full. # # Date.parse('2001-02-03') #=> # # Date.parse('20010203') #=> # # Date.parse('3rd Feb 2001') #=> # # def self.parse: (String str, ?boolish complete, ?Integer start) -> Date # Creates a new Date object by parsing from a string according to some typical # RFC 2822 formats. # # Date.rfc2822('Sat, 3 Feb 2001 00:00:00 +0000') # #=> # # def self.rfc2822: (String str, ?Integer start) -> Date # Creates a new Date object by parsing from a string according to some typical # RFC 3339 formats. # # Date.rfc3339('2001-02-03T04:05:06+07:00') #=> # # def self.rfc3339: (String str, ?Integer start) -> Date # Creates a new Date object by parsing from a string according to some typical # RFC 2822 formats. # # Date.rfc2822('Sat, 3 Feb 2001 00:00:00 +0000') # #=> # # def self.rfc822: (String str, ?Integer start) -> Date # Parses the given representation of date and time with the given template, and # creates a date object. strptime does not support specification of flags and # width unlike strftime. # # Date.strptime('2001-02-03', '%Y-%m-%d') #=> # # Date.strptime('03-02-2001', '%d-%m-%Y') #=> # # Date.strptime('2001-034', '%Y-%j') #=> # # Date.strptime('2001-W05-6', '%G-W%V-%u') #=> # # Date.strptime('2001 04 6', '%Y %U %w') #=> # # Date.strptime('2001 05 6', '%Y %W %u') #=> # # Date.strptime('sat3feb01', '%a%d%b%y') #=> # # # See also strptime(3) and #strftime. # def self.strptime: (String str, ?String format, ?Integer start) -> Date # Creates a date object denoting the present day. # # Date.today #=> # # def self.today: (?Integer start) -> Date # Returns true if the given calendar date is valid, and false if not. Valid in # this context is whether the arguments passed to this method would be accepted # by ::new. # # Date.valid_date?(2001,2,3) #=> true # Date.valid_date?(2001,2,29) #=> false # Date.valid_date?(2001,2,-1) #=> true # # See also ::jd and ::civil. # def self.valid_civil?: (Integer year, Integer month, Integer mday, ?Integer start) -> bool # Returns true if the given week date is valid, and false if not. # # Date.valid_commercial?(2001,5,6) #=> true # Date.valid_commercial?(2001,5,8) #=> false # # See also ::jd and ::commercial. # def self.valid_commercial?: (Integer cwyear, Integer cweek, Integer cwday, ?Integer start) -> bool # Returns true if the given calendar date is valid, and false if not. Valid in # this context is whether the arguments passed to this method would be accepted # by ::new. # # Date.valid_date?(2001,2,3) #=> true # Date.valid_date?(2001,2,29) #=> false # Date.valid_date?(2001,2,-1) #=> true # # See also ::jd and ::civil. # def self.valid_date?: (Integer year, Integer month, Integer mday, ?Integer start) -> bool # Just returns true. It's nonsense, but is for symmetry. # # Date.valid_jd?(2451944) #=> true # # See also ::jd. # def self.valid_jd?: (Integer jd, ?Integer start) -> bool # Returns true if the given ordinal date is valid, and false if not. # # Date.valid_ordinal?(2001,34) #=> true # Date.valid_ordinal?(2001,366) #=> false # # See also ::jd and ::ordinal. # def self.valid_ordinal?: (Integer year, Integer yday, ?Integer start) -> bool # Creates a new Date object by parsing from a string according to some typical # XML Schema formats. # # Date.xmlschema('2001-02-03') #=> # # def self.xmlschema: (String str, ?Integer start) -> Date public # Returns a date object pointing `other` days after self. The other should be a # numeric value. If the other is a fractional number, assumes its precision is # at most nanosecond. # # Date.new(2001,2,3) + 1 #=> # # DateTime.new(2001,2,3) + Rational(1,2) # #=> # # DateTime.new(2001,2,3) + Rational(-1,2) # #=> # # DateTime.jd(0,12) + DateTime.new(2001,2,3).ajd # #=> # # def +: ((Numeric & _ToR) other) -> Date # Returns the difference between the two dates if the other is a date object. # If the other is a numeric value, returns a date object pointing `other` days # before self. If the other is a fractional number, assumes its precision is at # most nanosecond. # # Date.new(2001,2,3) - 1 #=> # # DateTime.new(2001,2,3) - Rational(1,2) # #=> # # Date.new(2001,2,3) - Date.new(2001) # #=> (33/1) # DateTime.new(2001,2,3) - DateTime.new(2001,2,2,12) # #=> (1/2) # def -: ((Numeric & _ToR) other) -> Date | (Date other) -> Rational # Returns a date object pointing `n` months before self. The argument `n` should # be a numeric value. # # Date.new(2001,2,3) << 1 #=> # # Date.new(2001,2,3) << -2 #=> # # # When the same day does not exist for the corresponding month, the last day of # the month is used instead: # # Date.new(2001,3,28) << 1 #=> # # Date.new(2001,3,31) << 1 #=> # # # This also results in the following, possibly unexpected, behavior: # # Date.new(2001,3,31) << 2 #=> # # Date.new(2001,3,31) << 1 << 1 #=> # # # Date.new(2001,3,31) << 1 << -1 #=> # # def <<: (Integer month) -> Date # Compares the two dates and returns -1, zero, 1 or nil. The other should be a # date object or a numeric value as an astronomical Julian day number. # # Date.new(2001,2,3) <=> Date.new(2001,2,4) #=> -1 # Date.new(2001,2,3) <=> Date.new(2001,2,3) #=> 0 # Date.new(2001,2,3) <=> Date.new(2001,2,2) #=> 1 # Date.new(2001,2,3) <=> Object.new #=> nil # Date.new(2001,2,3) <=> Rational(4903887,2) #=> 0 # # See also Comparable. # def <=>: (untyped other) -> Integer? # Returns true if they are the same day. # # Date.new(2001,2,3) === Date.new(2001,2,3) # #=> true # Date.new(2001,2,3) === Date.new(2001,2,4) # #=> false # DateTime.new(2001,2,3) === DateTime.new(2001,2,3,12) # #=> true # DateTime.new(2001,2,3) === DateTime.new(2001,2,3,0,0,0,'+24:00') # #=> true # DateTime.new(2001,2,3) === DateTime.new(2001,2,4,0,0,0,'+24:00') # #=> false # def ===: (Date other) -> bool # Returns a date object pointing `n` months after self. The argument `n` should # be a numeric value. # # Date.new(2001,2,3) >> 1 #=> # # Date.new(2001,2,3) >> -2 #=> # # # When the same day does not exist for the corresponding month, the last day of # the month is used instead: # # Date.new(2001,1,28) >> 1 #=> # # Date.new(2001,1,31) >> 1 #=> # # # This also results in the following, possibly unexpected, behavior: # # Date.new(2001,1,31) >> 2 #=> # # Date.new(2001,1,31) >> 1 >> 1 #=> # # # Date.new(2001,1,31) >> 1 >> -1 #=> # # def >>: (Integer month) -> Date # Returns the astronomical Julian day number. This is a fractional number, # which is not adjusted by the offset. # # DateTime.new(2001,2,3,4,5,6,'+7').ajd #=> (11769328217/4800) # DateTime.new(2001,2,2,14,5,6,'-7').ajd #=> (11769328217/4800) # def ajd: () -> Rational # Returns the astronomical modified Julian day number. This is a fractional # number, which is not adjusted by the offset. # # DateTime.new(2001,2,3,4,5,6,'+7').amjd #=> (249325817/4800) # DateTime.new(2001,2,2,14,5,6,'-7').amjd #=> (249325817/4800) # def amjd: () -> Rational # Returns a string in asctime(3) format (but without "n\0" at the end). This # method is equivalent to strftime('%c'). # # See also asctime(3) or ctime(3). # def asctime: () -> String # Returns a string in asctime(3) format (but without "n\0" at the end). This # method is equivalent to strftime('%c'). # # See also asctime(3) or ctime(3). # def ctime: () -> String # Returns the day of calendar week (1-7, Monday is 1). # # Date.new(2001,2,3).cwday #=> 6 # def cwday: () -> Integer # Returns the calendar week number (1-53). # # Date.new(2001,2,3).cweek #=> 5 # def cweek: () -> Integer # Returns the calendar week based year. # # Date.new(2001,2,3).cwyear #=> 2001 # Date.new(2000,1,1).cwyear #=> 1999 # def cwyear: () -> Integer # Returns the day of the month (1-31). # # Date.new(2001,2,3).mday #=> 3 # def day: () -> Integer # This method is equivalent to step(min, -1){|date| ...}. # def downto: (Date min) { (Date) -> untyped } -> Date | (Date min) -> Enumerator[Date, Date] # This method is equivalent to new_start(Date::ENGLAND). # def england: () -> Date # Returns true if the date is Friday. # def friday?: () -> bool # This method is equivalent to new_start(Date::GREGORIAN). # def gregorian: () -> Date # Returns true if the date is on or after the day of calendar reform. # # Date.new(1582,10,15).gregorian? #=> true # (Date.new(1582,10,15) - 1).gregorian? #=> false # def gregorian?: () -> bool # This method is equivalent to strftime('%a, %d %b %Y %T GMT'). See also RFC # 2616. # def httpdate: () -> String # Returns the value as a string for inspection. # # Date.new(2001,2,3).inspect # #=> "#" # DateTime.new(2001,2,3,4,5,6,'-7').inspect # #=> "#" # def inspect: () -> String # This method is equivalent to strftime('%F'). # def iso8601: () -> String # This method is equivalent to new_start(Date::ITALY). # def italy: () -> Date # Returns the Julian day number. This is a whole number, which is adjusted by # the offset as the local time. # # DateTime.new(2001,2,3,4,5,6,'+7').jd #=> 2451944 # DateTime.new(2001,2,3,4,5,6,'-7').jd #=> 2451944 # def jd: () -> Integer # Returns a string in a JIS X 0301 format. # # Date.new(2001,2,3).jisx0301 #=> "H13.02.03" # def jisx0301: () -> String # This method is equivalent to new_start(Date::JULIAN). # def julian: () -> Date # Returns true if the date is before the day of calendar reform. # # Date.new(1582,10,15).julian? #=> false # (Date.new(1582,10,15) - 1).julian? #=> true # def julian?: () -> bool # Returns the Lilian day number. This is a whole number, which is adjusted by # the offset as the local time. # # Date.new(2001,2,3).ld #=> 152784 # def ld: () -> Integer # Returns true if the year is a leap year. # # Date.new(2000).leap? #=> true # Date.new(2001).leap? #=> false # def leap?: () -> bool # Returns the day of the month (1-31). # # Date.new(2001,2,3).mday #=> 3 # def mday: () -> Integer # Returns the modified Julian day number. This is a whole number, which is # adjusted by the offset as the local time. # # DateTime.new(2001,2,3,4,5,6,'+7').mjd #=> 51943 # DateTime.new(2001,2,3,4,5,6,'-7').mjd #=> 51943 # def mjd: () -> Integer # Returns the month (1-12). # # Date.new(2001,2,3).mon #=> 2 # def mon: () -> Integer # Returns true if the date is Monday. # def monday?: () -> bool # Returns the month (1-12). # # Date.new(2001,2,3).mon #=> 2 # def month: () -> Integer # Duplicates self and resets its day of calendar reform. # # d = Date.new(1582,10,15) # d.new_start(Date::JULIAN) #=> # # def new_start: (?Integer start) -> Date # Returns a date object denoting the following day. # def next: () -> Date # This method is equivalent to d + n. # def next_day: (?Integer day) -> Date # This method is equivalent to d >> n. # def next_month: (?Integer month) -> Date # This method is equivalent to d >> (n * 12). # # Date.new(2001,2,3).next_year #=> # # Date.new(2008,2,29).next_year #=> # # Date.new(2008,2,29).next_year(4) #=> # # def next_year: (?Integer year) -> Date # This method is equivalent to d - n. # def prev_day: (?Integer day) -> Date # This method is equivalent to d << n. # def prev_month: (?Integer month) -> Date # This method is equivalent to d << (n * 12). # # Date.new(2001,2,3).prev_year #=> # # Date.new(2008,2,29).prev_year #=> # # Date.new(2008,2,29).prev_year(4) #=> # # def prev_year: (?Integer year) -> Date # This method is equivalent to strftime('%a, %-d %b %Y %T %z'). # def rfc2822: () -> String # This method is equivalent to strftime('%FT%T%:z'). # def rfc3339: () -> String # This method is equivalent to strftime('%a, %-d %b %Y %T %z'). # def rfc822: () -> String # Returns true if the date is Saturday. # def saturday?: () -> bool # Returns the Julian day number denoting the day of calendar reform. # # Date.new(2001,2,3).start #=> 2299161.0 # Date.new(2001,2,3,Date::GREGORIAN).start #=> -Infinity # def start: () -> Float # Iterates evaluation of the given block, which takes a date object. The limit # should be a date object. # # Date.new(2001).step(Date.new(2001,-1,-1)).select{|d| d.sunday?}.size # #=> 52 # def step: (Date limit, ?Integer step) { (Date) -> untyped } -> Date | (Date limit, ?Integer step) -> ::Enumerator[Date, Date] # Formats date according to the directives in the given format string. The # directives begin with a percent (%) character. Any text not listed as a # directive will be passed through to the output string. # # A directive consists of a percent (%) character, zero or more flags, an # optional minimum field width, an optional modifier, and a conversion specifier # as follows. # # % # # Flags: # - don't pad a numerical output. # _ use spaces for padding. # 0 use zeros for padding. # ^ upcase the result string. # # change case. # # The minimum field width specifies the minimum width. # # The modifiers are "E", "O", ":", "::" and ":::". "E" and "O" are ignored. No # effect to result currently. # # Format directives: # # Date (Year, Month, Day): # %Y - Year with century (can be negative, 4 digits at least) # -0001, 0000, 1995, 2009, 14292, etc. # %C - year / 100 (round down. 20 in 2009) # %y - year % 100 (00..99) # # %m - Month of the year, zero-padded (01..12) # %_m blank-padded ( 1..12) # %-m no-padded (1..12) # %B - The full month name (``January'') # %^B uppercased (``JANUARY'') # %b - The abbreviated month name (``Jan'') # %^b uppercased (``JAN'') # %h - Equivalent to %b # # %d - Day of the month, zero-padded (01..31) # %-d no-padded (1..31) # %e - Day of the month, blank-padded ( 1..31) # # %j - Day of the year (001..366) # # Time (Hour, Minute, Second, Subsecond): # %H - Hour of the day, 24-hour clock, zero-padded (00..23) # %k - Hour of the day, 24-hour clock, blank-padded ( 0..23) # %I - Hour of the day, 12-hour clock, zero-padded (01..12) # %l - Hour of the day, 12-hour clock, blank-padded ( 1..12) # %P - Meridian indicator, lowercase (``am'' or ``pm'') # %p - Meridian indicator, uppercase (``AM'' or ``PM'') # # %M - Minute of the hour (00..59) # # %S - Second of the minute (00..60) # # %L - Millisecond of the second (000..999) # %N - Fractional seconds digits, default is 9 digits (nanosecond) # %3N millisecond (3 digits) %15N femtosecond (15 digits) # %6N microsecond (6 digits) %18N attosecond (18 digits) # %9N nanosecond (9 digits) %21N zeptosecond (21 digits) # %12N picosecond (12 digits) %24N yoctosecond (24 digits) # # Time zone: # %z - Time zone as hour and minute offset from UTC (e.g. +0900) # %:z - hour and minute offset from UTC with a colon (e.g. +09:00) # %::z - hour, minute and second offset from UTC (e.g. +09:00:00) # %:::z - hour, minute and second offset from UTC # (e.g. +09, +09:30, +09:30:30) # %Z - Equivalent to %:z (e.g. +09:00) # # Weekday: # %A - The full weekday name (``Sunday'') # %^A uppercased (``SUNDAY'') # %a - The abbreviated name (``Sun'') # %^a uppercased (``SUN'') # %u - Day of the week (Monday is 1, 1..7) # %w - Day of the week (Sunday is 0, 0..6) # # ISO 8601 week-based year and week number: # The week 1 of YYYY starts with a Monday and includes YYYY-01-04. # The days in the year before the first week are in the last week of # the previous year. # %G - The week-based year # %g - The last 2 digits of the week-based year (00..99) # %V - Week number of the week-based year (01..53) # # Week number: # The week 1 of YYYY starts with a Sunday or Monday (according to %U # or %W). The days in the year before the first week are in week 0. # %U - Week number of the year. The week starts with Sunday. (00..53) # %W - Week number of the year. The week starts with Monday. (00..53) # # Seconds since the Unix Epoch: # %s - Number of seconds since 1970-01-01 00:00:00 UTC. # %Q - Number of milliseconds since 1970-01-01 00:00:00 UTC. # # Literal string: # %n - Newline character (\n) # %t - Tab character (\t) # %% - Literal ``%'' character # # Combination: # %c - date and time (%a %b %e %T %Y) # %D - Date (%m/%d/%y) # %F - The ISO 8601 date format (%Y-%m-%d) # %v - VMS date (%e-%b-%Y) # %x - Same as %D # %X - Same as %T # %r - 12-hour time (%I:%M:%S %p) # %R - 24-hour time (%H:%M) # %T - 24-hour time (%H:%M:%S) # %+ - date(1) (%a %b %e %H:%M:%S %Z %Y) # # This method is similar to the strftime() function defined in ISO C and POSIX. # Several directives (%a, %A, %b, %B, %c, %p, %r, %x, %X, %E*, %O* and %Z) are # locale dependent in the function. However, this method is locale independent. # So, the result may differ even if the same format string is used in other # systems such as C. It is good practice to avoid %x and %X because there are # corresponding locale independent representations, %D and %T. # # Examples: # # d = DateTime.new(2007,11,19,8,37,48,"-06:00") # #=> # # d.strftime("Printed on %m/%d/%Y") #=> "Printed on 11/19/2007" # d.strftime("at %I:%M%p") #=> "at 08:37AM" # # Various ISO 8601 formats: # %Y%m%d => 20071119 Calendar date (basic) # %F => 2007-11-19 Calendar date (extended) # %Y-%m => 2007-11 Calendar date, reduced accuracy, specific month # %Y => 2007 Calendar date, reduced accuracy, specific year # %C => 20 Calendar date, reduced accuracy, specific century # %Y%j => 2007323 Ordinal date (basic) # %Y-%j => 2007-323 Ordinal date (extended) # %GW%V%u => 2007W471 Week date (basic) # %G-W%V-%u => 2007-W47-1 Week date (extended) # %GW%V => 2007W47 Week date, reduced accuracy, specific week (basic) # %G-W%V => 2007-W47 Week date, reduced accuracy, specific week (extended) # %H%M%S => 083748 Local time (basic) # %T => 08:37:48 Local time (extended) # %H%M => 0837 Local time, reduced accuracy, specific minute (basic) # %H:%M => 08:37 Local time, reduced accuracy, specific minute (extended) # %H => 08 Local time, reduced accuracy, specific hour # %H%M%S,%L => 083748,000 Local time with decimal fraction, comma as decimal sign (basic) # %T,%L => 08:37:48,000 Local time with decimal fraction, comma as decimal sign (extended) # %H%M%S.%L => 083748.000 Local time with decimal fraction, full stop as decimal sign (basic) # %T.%L => 08:37:48.000 Local time with decimal fraction, full stop as decimal sign (extended) # %H%M%S%z => 083748-0600 Local time and the difference from UTC (basic) # %T%:z => 08:37:48-06:00 Local time and the difference from UTC (extended) # %Y%m%dT%H%M%S%z => 20071119T083748-0600 Date and time of day for calendar date (basic) # %FT%T%:z => 2007-11-19T08:37:48-06:00 Date and time of day for calendar date (extended) # %Y%jT%H%M%S%z => 2007323T083748-0600 Date and time of day for ordinal date (basic) # %Y-%jT%T%:z => 2007-323T08:37:48-06:00 Date and time of day for ordinal date (extended) # %GW%V%uT%H%M%S%z => 2007W471T083748-0600 Date and time of day for week date (basic) # %G-W%V-%uT%T%:z => 2007-W47-1T08:37:48-06:00 Date and time of day for week date (extended) # %Y%m%dT%H%M => 20071119T0837 Calendar date and local time (basic) # %FT%R => 2007-11-19T08:37 Calendar date and local time (extended) # %Y%jT%H%MZ => 2007323T0837Z Ordinal date and UTC of day (basic) # %Y-%jT%RZ => 2007-323T08:37Z Ordinal date and UTC of day (extended) # %GW%V%uT%H%M%z => 2007W471T0837-0600 Week date and local time and difference from UTC (basic) # %G-W%V-%uT%R%:z => 2007-W47-1T08:37-06:00 Week date and local time and difference from UTC (extended) # # See also strftime(3) and ::strptime. # def strftime: (?String format) -> String # Returns a date object denoting the following day. # def succ: () -> Date # Returns true if the date is Sunday. # def sunday?: () -> bool # Returns true if the date is Thursday. # def thursday?: () -> bool # Returns self. # def to_date: () -> Date # Returns a DateTime object which denotes self. # def to_datetime: () -> DateTime # Returns a string in an ISO 8601 format. (This method doesn't use the expanded # representations.) # # Date.new(2001,2,3).to_s #=> "2001-02-03" # def to_s: () -> String # Returns a Time object which denotes self. If self is a julian date, convert it # to a gregorian date before converting it to Time. # def to_time: () -> Time # Returns true if the date is Tuesday. # def tuesday?: () -> bool # This method is equivalent to step(max, 1){|date| ...}. # def upto: (Date max) { (Date) -> untyped } -> Date | (Date max) -> ::Enumerator[Date, Date] # Returns the day of week (0-6, Sunday is zero). # # Date.new(2001,2,3).wday #=> 6 # def wday: () -> Integer # Returns true if the date is Wednesday. # def wednesday?: () -> bool # This method is equivalent to strftime('%F'). # def xmlschema: () -> String # Returns the day of the year (1-366). # # Date.new(2001,2,3).yday #=> 34 # def yday: () -> Integer # Returns the year. # # Date.new(2001,2,3).year #=> 2001 # (Date.new(1,1,1) - 1).year #=> 0 # def year: () -> Integer end # An array of strings of abbreviated day names in English. The first is "Sun". # Date::ABBR_DAYNAMES: Array[String] # An array of strings of abbreviated month names in English. The first element # is nil. # Date::ABBR_MONTHNAMES: Array[String?] # An array of strings of the full names of days of the week in English. The # first is "Sunday". # Date::DAYNAMES: Array[String] # The Julian day number of the day of calendar reform for England and her # colonies. # Date::ENGLAND: Integer # The Julian day number of the day of calendar reform for the proleptic # Gregorian calendar. # Date::GREGORIAN: Integer # The Julian day number of the day of calendar reform for Italy and some # catholic countries. # Date::ITALY: Integer # The Julian day number of the day of calendar reform for the proleptic Julian # calendar. # Date::JULIAN: Integer # An array of strings of full month names in English. The first element is nil. # Date::MONTHNAMES: Array[String?]