Object
Class representing a date.
See the documentation to the file date.rb for an overview.
Internally, the date is represented as an Astronomical Julian Day Number,
ajd
. The Day of Calendar Reform, sg
, is also
stored, for conversions to other date formats. (There is also an
of
field for a time zone offset, but this is only for the use
of the DateTime subclass.)
A new Date object is created using one of the object creation class methods named after the corresponding date format, and the arguments appropriate to that date format; for instance, ::civil (aliased to ::new) with year, month, and day-of-month, or ::ordinal with year and day-of-year. All of these object creation class methods also take the Day of Calendar Reform as an optional argument.
Date objects are immutable once created.
Once a Date has been created, date values can be retrieved for the different date formats supported using instance methods. For instance, mon() gives the Civil month, cwday() gives the Commercial day of the week, and yday() gives the Ordinal day of the year. Date values can be retrieved in any format, regardless of what format was used to create the Date instance.
The Date class includes the Comparable module, allowing date objects to be compared and sorted, ranges of dates to be created, and so forth.
format.rb: Written by Tadayoshi Funaba 1999-2008 $Id: format.rb,v 2.43 2008-01-17 20:16:31+09 tadf Exp $
Abbreviated day names, in English.
Abbreviated month names, in English.
Full names of days of the week, in English. Days of the week count from 0 to 6 (except in the commercial week); a day's numerical representation indexed into this array gives the name of that day.
The Julian Day Number of the Day of Calendar Reform for England and her Colonies.
A constant used to indicate that a Date should always use the Gregorian calendar.
The Julian Day Number of the Day of Calendar Reform for Italy and the Catholic countries.
A constant used to indicate that a Date should always use the Julian calendar.
Full month names, in English. Months count from 1 to 12; a month's numerical representation indexed into this array gives the name of that month (hence the first element is nil).
# File date/format.rb, line 1030 def self._parse(str, comp=true) str = str.dup e = Format::Bag.new e._comp = comp str.gsub!(/[^-+',.\/:@[:alnum:]\[\]]+/, ' ') _parse_time(str, e) # || _parse_beat(str, e) _parse_day(str, e) _parse_eu(str, e) || _parse_us(str, e) || _parse_iso(str, e) || _parse_jis(str, e) || _parse_vms(str, e) || _parse_sla(str, e) || _parse_dot(str, e) || _parse_iso2(str, e) || _parse_year(str, e) || _parse_mon(str, e) || _parse_mday(str, e) || _parse_ddd(str, e) if str.sub!(/\b(bc\b|bce\b|b\.c\.|b\.c\.e\.)/i, ' ') if e.year e.year = -e.year + 1 end end if str.sub!(/\A\s*(\d{1,2})\s*\z/, ' ') if e.hour && !e.mday v = $1.to_i if (1..31) === v e.mday = v end end if e.mday && !e.hour v = $1.to_i if (0..24) === v e.hour = v end end end if e._comp if e.cwyear if e.cwyear >= 0 && e.cwyear <= 99 e.cwyear += if e.cwyear >= 69 then 1900 else 2000 end end end if e.year if e.year >= 0 && e.year <= 99 e.year += if e.year >= 69 then 1900 else 2000 end end end end e.offset ||= zone_to_diff(e.zone) if e.zone e.to_hash end
# File date/format.rb, line 574 def self._strptime(str, fmt='%F') str = str.dup e = Format::Bag.new return unless _strptime_i(str, fmt, e) if e._cent if e.cwyear e.cwyear += e._cent * 100 end if e.year e. year += e._cent * 100 end end if e._merid if e.hour e.hour %= 12 e.hour += e._merid end end unless str.empty? e.leftover = str end e.to_hash end
Create a new Date object for the Civil Date specified by year y
, month
m
, and day-of-month d
.
m
and d
can be negative, in which case they count
backwards from the end of the year and the end of the month respectively.
No wraparound is performed, however, and invalid values cause an
ArgumentError to be raised. can be negative
y
defaults to -4712, m
to 1, and d
to 1; this is Julian Day Number day 0.
sg
specifies the Day of Calendar Reform.
# File date.rb, line 807 def self.civil(y=-4712, m=1, d=1, sg=ITALY) unless jd = _valid_civil?(y, m, d, sg) raise ArgumentError, 'invalid date' end new!(jd_to_ajd(jd, 0, 0), 0, sg) end
Create a new Date object for the Commercial Date specified by year y
, week-of-year
w
, and day-of-week d
.
Monday is day-of-week 1; Sunday is day-of-week 7.
w
and d
can be negative, in which case they count
backwards from the end of the year and the end of the week respectively.
No wraparound is performed, however, and invalid values cause an
ArgumentError to be raised.
y
defaults to -4712, w
to 1, and d
to 1; this is Julian Day Number day 0.
sg
specifies the Day of Calendar Reform.
# File date.rb, line 830 def self.commercial(y=-4712, w=1, d=1, sg=ITALY) unless jd = _valid_commercial?(y, w, d, sg) raise ArgumentError, 'invalid date' end new!(jd_to_ajd(jd, 0, 0), 0, sg) end
Is a year a leap year in the Gregorian calendar?
All years divisible by 4 are leap years in the Gregorian calendar, except for years divisible by 100 and not by 400.
# File date.rb, line 726 def self.gregorian_leap? (y) y % 4 == 0 && y % 100 != 0 || y % 400 == 0 end
Create a new Date object from a Julian Day Number.
jd
is the Julian Day Number; if not specified, it defaults to
0. sg
specifies the Day of Calendar Reform.
# File date.rb, line 772 def self.jd(jd=0, sg=ITALY) jd = _valid_jd?(jd, sg) new!(jd_to_ajd(jd, 0, 0), 0, sg) end
Is a year a leap year in the Julian calendar?
All years divisible by 4 are leap years in the Julian calendar.
# File date.rb, line 720 def self.julian_leap? (y) y % 4 == 0 end
NOTE this is the documentation for the method new!(). If you are reading this as the documentation for new(), that is because rdoc doesn't fully support the aliasing of the initialize() method. new() is in fact an alias for civil(): read the documentation for that method instead.
Create a new Date object.
ajd
is the Astronomical Julian Day Number. of
is
the offset from UTC as a fraction of a day. Both default to 0.
sg
specifies the Day of Calendar Reform to use for this Date object.
Using one of the factory methods such as ::civil is generally easier and safer.
# File date.rb, line 1138 def initialize(ajd=0, of=0, sg=ITALY) @ajd, @of, @sg = ajd, of, sg @__ca__ = {} end
Create a new Date object from an Ordinal Date, specified by year y
and day-of-year
d
. d
can be negative, in which it counts
backwards from the end of the year. No year wraparound is performed,
however. An invalid value for d
results in an ArgumentError
being raised.
y
defaults to -4712, and d
to 1; this is Julian
Day Number day 0.
sg
specifies the Day of Calendar Reform.
# File date.rb, line 787 def self.ordinal(y=-4712, d=1, sg=ITALY) unless jd = _valid_ordinal?(y, d, sg) raise ArgumentError, 'invalid date' end new!(jd_to_ajd(jd, 0, 0), 0, sg) end
Create a new Date object by parsing from a String, without specifying the format.
str
is a String holding a date representation.
comp
specifies whether to interpret 2-digit years as 19XX
(>= 69) or 20XX (< 69); the default is not to. The method will
attempt to parse a date from the String using various heuristics; see
#_parse in date/format.rb for more details. If parsing fails, an
ArgumentError will be raised.
The default str
is '-4712-01-01'; this is Julian Day
Number day 0.
sg
specifies the Day of Calendar Reform.
# File date.rb, line 1064 def self.parse(str='-4712-01-01', comp=true, sg=ITALY) elem = _parse(str, comp) new_by_frags(elem, sg) end
Create a new Date object by parsing from a String according to a specified format.
str
is a String holding a date representation.
fmt
is the format that the date is in. See date/format.rb for
details on supported formats.
The default str
is '-4712-01-01', and the default
fmt
is '%F', which means Year-Month-Day_of_Month. This
gives Julian Day Number day 0.
sg
specifies the Day of Calendar Reform.
An ArgumentError will be raised if str
cannot be parsed.
# File date.rb, line 1044 def self.strptime(str='-4712-01-01', fmt='%F', sg=ITALY) elem = _strptime(str, fmt) new_by_frags(elem, sg) end
Create a new Date object representing today.
sg
specifies the Day of Calendar Reform.
# File date.rb, line 1795 def self.today(sg=ITALY) t = Time.now jd = civil_to_jd(t.year, t.mon, t.mday, sg) new!(jd_to_ajd(jd, 0, 0), 0, sg) end
# File date.rb, line 739 def self.valid_civil? (y, m, d, sg=ITALY) !!_valid_civil?(y, m, d, sg) end
# File date.rb, line 745 def self.valid_commercial? (y, w, d, sg=ITALY) !!_valid_commercial?(y, w, d, sg) end
Return a new Date object that is n
days later than the current one.
n
may be a negative value, in which case the new Date is earlier than the current one; however, #-()
might be more intuitive.
If n
is not a Numeric, a TypeError will be thrown. In
particular, two Dates cannot be added to each other.
# File date.rb, line 1336 def + (n) case n when Numeric; return self.class.new!(@ajd + n, @of, @sg) end raise TypeError, 'expected numeric' end
If x
is a Numeric value, create a new Date object that is x
days earlier than
the current one.
If x
is a Date, return the number of
days between the two dates; or, more precisely, how many days later the
current date is than x
.
If x
is neither Numeric nor a Date, a
TypeError is raised.
# File date.rb, line 1351 def - (x) case x when Numeric; return self.class.new!(@ajd - x, @of, @sg) when Date; return @ajd - x.ajd end raise TypeError, 'expected numeric or date' end
Return a new Date object that is n
months earlier than the current one.
If the day-of-the-month of the current Date is greater than the last day of the target month, the day-of-the-month of the returned Date will be the last day of the target month.
# File date.rb, line 1420 def << (n) self >> -n end
Compare this date with another date.
other
can also be a Numeric value, in which case it is
interpreted as an Astronomical Julian Day Number.
Comparison is by Astronomical Julian Day Number, including fractional days. This means that both the time and the timezone offset are taken into account when comparing two DateTime instances. When comparing a DateTime instance with a Date instance, the time of the latter will be considered as falling on midnight UTC.
# File date.rb, line 1370 def <=> (other) case other when Numeric; return @ajd <=> other when Date; return @ajd <=> other.ajd end nil end
The relationship operator for Date.
Compares dates by Julian Day Number. When comparing two DateTime instances, or a DateTime with a Date, the instances will be regarded as equivalent if they fall on the same date in local time.
# File date.rb, line 1384 def === (other) case other when Numeric; return jd == other when Date; return jd == other.jd end false end
Return a new Date object that is n
months later than the current one.
If the day-of-the-month of the current Date is greater than the last day of the target month, the day-of-the-month of the returned Date will be the last day of the target month.
# File date.rb, line 1406 def >> (n) y, m = (year * 12 + (mon - 1) + n).divmod(12) m, = (m + 1) .divmod(1) d = mday d -= 1 until jd2 = _valid_civil?(y, m, d, @sg) self + (jd2 - jd) end
Get the date as an Astronomical Julian Day Number.
# File date.rb, line 1144 def ajd() @ajd end
Get the date as an Astronomical Modified Julian Day Number.
# File date.rb, line 1147 def amjd() ajd_to_amjd(@ajd) end
alias_method :format, :strftime
# File date/format.rb, line 341 def asctime() strftime('%c') end
Get the commercial day of the week of this date. Monday is commercial day-of-week 1; Sunday is commercial day-of-week 7.
# File date.rb, line 1244 def cwday() commercial[2] end
Get the commercial week of the year of this date.
# File date.rb, line 1240 def cweek() commercial[1] end
Get the commercial year of this date. See Commercial Date in the introduction for how this differs from the normal year.
# File date.rb, line 1237 def cwyear() commercial[0] end
Get any fractional day part of the date.
# File date.rb, line 1155 def day_fraction() ajd_to_jd(@ajd, @of)[1] end
Step backward one day at a time until we reach min
(inclusive), yielding each date as we go.
# File date.rb, line 1460 def downto(min, &block) # :yield: date step(min, -1, &block) end
Create a copy of this Date object that uses the English/Colonial Day of Calendar Reform.
# File date.rb, line 1306 def england() new_start(self.class::ENGLAND) end
Create a copy of this Date object that always uses the Gregorian Calendar.
# File date.rb, line 1314 def gregorian() new_start(self.class::GREGORIAN) end
Is the current date new-style (Gregorian Calendar)?
# File date.rb, line 1274 def gregorian? () !julian? end
Calculate a hash value for this date.
# File date.rb, line 1470 def hash() @ajd.hash end
Get the hour of this date.
# File date.rb, line 1213 def hour() time[0] end
Return internal object state as a programmer-readable string.
# File date.rb, line 1473 def inspect format('#<%s: %s (%s,%s,%s)>', self.class, to_s, @ajd, @of, @sg) end
Create a copy of this Date object that uses the Italian/Catholic Day of Calendar Reform.
# File date.rb, line 1302 def italy() new_start(self.class::ITALY) end
Get the date as a Julian Day Number.
# File date.rb, line 1152 def jd() ajd_to_jd(@ajd, @of)[0] end
# File date/format.rb, line 357 def jisx0301 if jd < 2405160 iso8601 else case jd when 2405160...2419614 g = 'M%02d' % (year - 1867) when 2419614...2424875 g = 'T%02d' % (year - 1911) when 2424875...2447535 g = 'S%02d' % (year - 1925) else g = 'H%02d' % (year - 1988) end g + strftime('.%m.%d') end end
Create a copy of this Date object that always uses the Julian Calendar.
# File date.rb, line 1310 def julian() new_start(self.class::JULIAN) end
Is the current date old-style (Julian Calendar)?
# File date.rb, line 1271 def julian? () jd < @sg end
Get the date as the number of days since the Day of Calendar Reform (in Italy and the Catholic countries).
# File date.rb, line 1162 def ld() jd_to_ld(jd) end
Is this a leap year?
# File date.rb, line 1287 def leap? jd_to_civil(civil_to_jd(year, 3, 1, fix_style) - 1, fix_style)[-1] == 29 end
Dump to Marshal format.
# File date.rb, line 1483 def marshal_dump() [@ajd, @of, @sg] end
Load from Marshal format.
# File date.rb, line 1486 def marshal_load(a) @ajd, @of, @sg, = a @__ca__ = {} end
Get the day-of-the-month of this date.
# File date.rb, line 1195 def mday() civil[2] end
Get the minute of this date.
# File date.rb, line 1216 def min() time[1] end
Get the date as a Modified Julian Day Number.
# File date.rb, line 1158 def mjd() jd_to_mjd(jd) end
Get the month of this date.
January is month 1.
# File date.rb, line 1192 def mon() civil[1] end
# File date.rb, line 1318 def new_offset(of=0) if String === of of = Rational(zone_to_diff(of) || 0, 86400) end self.class.new!(@ajd, of, @sg) end
Create a copy of this Date object using a new Day of Calendar Reform.
# File date.rb, line 1298 def new_start(sg=self.class::ITALY) self.class.new!(@ajd, @of, sg) end
Return a new Date one day after this one.
# File date.rb, line 1396 def next() next_day end
# File date.rb, line 1425 def next_year(n=1) self >> n * 12 end
# File date.rb, line 1426 def prev_year(n=1) self << n * 12 end
# File date/format.rb, line 351 def rfc2822() strftime('%a, %-d %b %Y %T %z') end
Get the second of this date.
# File date.rb, line 1219 def sec() time[2] end
Get the fraction-of-a-second of this date.
# File date.rb, line 1222 def sec_fraction() time[3] end
When is the Day of Calendar Reform for this Date object?
# File date.rb, line 1295 def start() @sg end
Step the current date forward step
days at a time (or
backward, if step
is negative) until we reach
limit
(inclusive), yielding the resultant date at each step.
# File date.rb, line 1434 def step(limit, step=1) # :yield: date =begin if step.zero? raise ArgumentError, "step can't be 0" end =end unless block_given? return to_enum(:step, limit, step) end da = self op = %w(- <= >=)[step <=> 0] while da.__send__(op, limit) yield da da += step end self end
# File date/format.rb, line 215 def strftime(fmt='%F') fmt.gsub(/%([-_0^#]+)?(\d+)?([EO]?(?::{1,3}z|.))/m) do f = {} m = $& s, w, c = $1, $2, $3 if s s.scan(/./) do |k| case k when '-'; f[:p] = '-' when '_'; f[:p] = "\s" when '0'; f[:p] = '0' when '^'; f[:u] = true when '#'; f[:x] = true end end end if w f[:w] = w.to_i end case c when 'A'; emit_ad(DAYNAMES[wday], 0, f) when 'a'; emit_ad(ABBR_DAYNAMES[wday], 0, f) when 'B'; emit_ad(MONTHNAMES[mon], 0, f) when 'b'; emit_ad(ABBR_MONTHNAMES[mon], 0, f) when 'C', 'EC'; emit_sn((year / 100).floor, 2, f) when 'c', 'Ec'; emit_a(strftime('%a %b %e %H:%M:%S %Y'), 0, f) when 'D'; emit_a(strftime('%m/%d/%y'), 0, f) when 'd', 'Od'; emit_n(mday, 2, f) when 'e', 'Oe'; emit_a(mday, 2, f) when 'F' if m == '%F' format('%.4d-%02d-%02d', year, mon, mday) # 4p else emit_a(strftime('%Y-%m-%d'), 0, f) end when 'G'; emit_sn(cwyear, 4, f) when 'g'; emit_n(cwyear % 100, 2, f) when 'H', 'OH'; emit_n(hour, 2, f) when 'h'; emit_ad(strftime('%b'), 0, f) when 'I', 'OI'; emit_n((hour % 12).nonzero? || 12, 2, f) when 'j'; emit_n(yday, 3, f) when 'k'; emit_a(hour, 2, f) when 'L' f[:p] = nil w = f[:w] || 3 u = 10**w emit_n((sec_fraction * u).floor, w, f) when 'l'; emit_a((hour % 12).nonzero? || 12, 2, f) when 'M', 'OM'; emit_n(min, 2, f) when 'm', 'Om'; emit_n(mon, 2, f) when 'N' f[:p] = nil w = f[:w] || 9 u = 10**w emit_n((sec_fraction * u).floor, w, f) when 'n'; emit_a("\n", 0, f) when 'P'; emit_ad(strftime('%p').downcase, 0, f) when 'p'; emit_au(if hour < 12 then 'AM' else 'PM' end, 0, f) when 'Q' s = ((ajd - UNIX_EPOCH_IN_AJD) / MILLISECONDS_IN_DAY).round emit_sn(s, 1, f) when 'R'; emit_a(strftime('%H:%M'), 0, f) when 'r'; emit_a(strftime('%I:%M:%S %p'), 0, f) when 'S', 'OS'; emit_n(sec, 2, f) when 's' s = ((ajd - UNIX_EPOCH_IN_AJD) / SECONDS_IN_DAY).round emit_sn(s, 1, f) when 'T' if m == '%T' format('%02d:%02d:%02d', hour, min, sec) # 4p else emit_a(strftime('%H:%M:%S'), 0, f) end when 't'; emit_a("\t", 0, f) when 'U', 'W', 'OU', 'OW' emit_n(if c[-1,1] == 'U' then wnum0 else wnum1 end, 2, f) when 'u', 'Ou'; emit_n(cwday, 1, f) when 'V', 'OV'; emit_n(cweek, 2, f) when 'v'; emit_a(strftime('%e-%b-%Y'), 0, f) when 'w', 'Ow'; emit_n(wday, 1, f) when 'X', 'EX'; emit_a(strftime('%H:%M:%S'), 0, f) when 'x', 'Ex'; emit_a(strftime('%m/%d/%y'), 0, f) when 'Y', 'EY'; emit_sn(year, 4, f) when 'y', 'Ey', 'Oy'; emit_n(year % 100, 2, f) when 'Z'; emit_au(strftime('%:z'), 0, f) when /\A(:{0,3})z/ t = $1.size sign = if offset < 0 then -1 else +1 end fr = offset.abs ss = fr.div(SECONDS_IN_DAY) # 4p hh, ss = ss.divmod(3600) mm, ss = ss.divmod(60) if t == 3 if ss.nonzero? then t = 2 elsif mm.nonzero? then t = 1 else t = -1 end end case t when -1 tail = [] sep = '' when 0 f[:w] -= 2 if f[:w] tail = ['%02d' % mm] sep = '' when 1 f[:w] -= 3 if f[:w] tail = ['%02d' % mm] sep = ':' when 2 f[:w] -= 6 if f[:w] tail = ['%02d' % mm, '%02d' % ss] sep = ':' end ([emit_z(sign * hh, 2, f)] + tail).join(sep) when '%'; emit_a('%', 0, f) when '+'; emit_a(strftime('%a %b %e %H:%M:%S %Z %Y'), 0, f) else m end end end
# File date.rb, line 529 def time_to_day_fraction(h, min, s) Rational(h * 3600 + min * 60 + s, 86400) # 4p end
# File date.rb, line 1790 def to_datetime() DateTime.new!(jd_to_ajd(jd, 0, 0), @of, @sg) end
Return the date as a human-readable string.
The format used is YYYY-MM-DD.
# File date.rb, line 1480 def to_s() format('%.4d-%02d-%02d', year, mon, mday) end
# File date.rb, line 1788 def to_time() Time.local(year, mon, mday) end
Step forward one day at a time until we reach max
(inclusive),
yielding each date as we go.
# File date.rb, line 1454 def upto(max, &block) # :yield: date step(max, +1, &block) end
Get the week day of this date. Sunday is day-of-week 0; Saturday is day-of-week 6.
# File date.rb, line 1248 def wday() jd_to_wday(jd) end
Get the day-of-the-year of this date.
January 1 is day-of-the-year 1
# File date.rb, line 1187 def yday() ordinal[1] end