Class: Date

Inherits:
Object
  • Object
show all
Includes:
Comparable
Defined in:
lib/date.rb,
lib/date.rb,
lib/date.rb,
lib/date/format.rb

Overview

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, Date::civil() (aliased to Date::new()) with year, month, and day-of-month, or Date::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.

Direct Known Subclasses

DateTime

Defined Under Namespace

Modules: Format Classes: Infinity

Constant Summary collapse

MONTHNAMES =

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).

[nil] + %w(January February March April May June July
August September October November December)
DAYNAMES =

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.

%w(Sunday Monday Tuesday Wednesday Thursday Friday Saturday)
ABBR_MONTHNAMES =

Abbreviated month names, in English.

[nil] + %w(Jan Feb Mar Apr May Jun
Jul Aug Sep Oct Nov Dec)
ABBR_DAYNAMES =

Abbreviated day names, in English.

%w(Sun Mon Tue Wed Thu Fri Sat)
ITALY =

The Julian Day Number of the Day of Calendar Reform for Italy and the Catholic countries.

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ENGLAND =

The Julian Day Number of the Day of Calendar Reform for England and her Colonies.

2361222
JULIAN =

A constant used to indicate that a Date should always use the Julian calendar.

Infinity.new
GREGORIAN =

A constant used to indicate that a Date should always use the Gregorian calendar.

-Infinity.new
UNIXEPOCH =

1970-01-01 :nodoc:

2440588

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(ajd = 0, of = 0, sg = ITALY) ⇒ Date

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 Date::civil is generally easier and safer.



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# File 'lib/date.rb', line 1015

def initialize(ajd=0, of=0, sg=ITALY) @ajd, @of, @sg = ajd, of, sg end

Class Method Details

._load(str) ⇒ Object

Load from Marshall format.



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# File 'lib/date.rb', line 1351

def self._load(str)
  a = Marshal.load(str)
  if a.size == 2
    ajd,     sg = a
         of = 0
    ajd -= 1.to_r/2
  else
    ajd, of, sg = a
  end
  new!(ajd, of, sg)
end

._parse(str, comp = false) ⇒ Object 



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# File 'lib/date/format.rb', line 958

def self._parse(str, comp=false)
  str = str.dup

  e = Format::Bag.new

  e._comp = comp

  str.gsub!(/[^-+',.\/:0-9@a-z\x80-\xff]+/in, ' ')

  _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_us(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\.)/in, ' ')
    if e.year
	e.year = -e.year + 1
    end
  end

  if str.sub!(/\A\s*(\d{1,2})\s*\z/n, ' ')
    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 and e.year
    if e.year >= 0 and e.year <= 99
	if e.year >= 69
 e.year += 1900
	else
 e.year += 2000
	end
    end
  end

  e.offset ||= zone_to_diff(e.zone) if e.zone

  e.to_hash
end

._strptime(str, fmt = '%F') ⇒ Object 



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# File 'lib/date/format.rb', line 581

def self._strptime(str, fmt='%F')
  e = Format::Bag.new
  return unless _strptime_i(str.dup, 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

  e.to_hash
end

.ajd_to_amjd(ajd) ⇒ Object

Convert an Astronomical Julian Day Number to an Astronomical Modified Julian Day Number.



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# File 'lib/date.rb', line 513

def self.ajd_to_amjd(ajd) ajd - 4800001.to_r/2 end

.ajd_to_jd(ajd, of = 0) ⇒ Object

Convert an Astronomical Julian Day Number to a (civil) Julian Day Number.

ajd is the Astronomical Julian Day Number to convert. of is the offset from UTC as a fraction of a day (defaults to 0).

Returns the (civil) Julian Day Number as [day_number, fraction] where fraction is always 1/2.



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# File 'lib/date.rb', line 479

def self.ajd_to_jd(ajd, of=0) (ajd + of + 1.to_r/2).divmod(1) end

.amjd_to_ajd(amjd) ⇒ Object

Convert an Astronomical Modified Julian Day Number to an Astronomical Julian Day Number.



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# File 'lib/date.rb', line 509

def self.amjd_to_ajd(amjd) amjd + 4800001.to_r/2 end

.civil(y = -4712,, m = 1, d = 1, sg = ITALY) ⇒ Object

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.



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# File 'lib/date.rb', line 725

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

.civil_to_jd(y, m, d, sg = GREGORIAN) ⇒ Object

Convert a Civil Date to a Julian Day Number. y, m, and d are the year, month, and day of the month. sg specifies the Day of Calendar Reform.

Returns the corresponding Julian Day Number.



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# File 'lib/date.rb', line 383

def self.civil_to_jd(y, m, d, sg=GREGORIAN)
  if m <= 2
    y -= 1
    m += 12
  end
  a = (y / 100.0).floor
  b = 2 - a + (a / 4.0).floor
  jd = (365.25 * (y + 4716)).floor +
    (30.6001 * (m + 1)).floor +
    d + b - 1524
  if julian?(jd, sg)
    jd -= b
  end
  jd
end

.commercial(y = 1582, w = 41, d = 5, sg = ITALY) ⇒ Object

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 1582, w to 41, and d to 5, the Day of Calendar Reform for Italy and the Catholic countries.

sg specifies the Day of Calendar Reform.



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# File 'lib/date.rb', line 748

def self.commercial(y=1582, w=41, d=5, 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

.commercial_to_jd(y, w, d, ns = GREGORIAN) ⇒ Object

Convert a Commercial Date to a Julian Day Number.

y, w, and d are the (commercial) year, week of the year, and day of the week of the Commercial Date to convert. sg specifies the Day of Calendar Reform.



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# File 'lib/date.rb', line 432

def self.commercial_to_jd(y, w, d, ns=GREGORIAN)
  jd = civil_to_jd(y, 1, 4, ns)
  (jd - (((jd - 1) + 1) % 7)) +
    7 * (w - 1) +
    (d - 1)
end

.day_fraction_to_time(fr) ⇒ Object

Convert a fractional day fr to [hours, minutes, seconds, fraction_of_a_second]



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# File 'lib/date.rb', line 494

def self.day_fraction_to_time(fr)
  h,   fr = fr.divmod(1.to_r/24)
  min, fr = fr.divmod(1.to_r/1440)
  s,   fr = fr.divmod(1.to_r/86400)
  return h, min, s, fr
end

.gregorian?(jd, sg) ⇒ Boolean

Does a given Julian Day Number fall inside the new-style (Gregorian) calendar?

The reverse of self.os? See the documentation for that method for more details.

Returns:

  • (Boolean) 


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# File 'lib/date.rb', line 345

def self.gregorian? (jd, sg) !julian?(jd, sg) end

.gregorian_leap?(y) ⇒ Boolean Also known as: leap?

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.

Returns:

  • (Boolean) 


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# File 'lib/date.rb', line 545

def self.gregorian_leap? (y) y % 4 == 0 && y % 100 != 0 || y % 400 == 0 end

.jd(jd = 0, sg = ITALY) ⇒ Object

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.



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# File 'lib/date.rb', line 690

def self.jd(jd=0, sg=ITALY)
  jd = valid_jd?(jd, sg)
  new!(jd_to_ajd(jd, 0, 0), 0, sg)
end

.jd_to_ajd(jd, fr, of = 0) ⇒ Object

Convert a (civil) Julian Day Number to an Astronomical Julian Day Number.

jd is the Julian Day Number to convert, and fr is a fractional day. of is the offset from UTC as a fraction of a day (defaults to 0).

Returns the Astronomical Julian Day Number as a single numeric value.



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# File 'lib/date.rb', line 490

def self.jd_to_ajd(jd, fr, of=0) jd + fr - of - 1.to_r/2 end

.jd_to_civil(jd, sg = GREGORIAN) ⇒ Object

Convert a Julian Day Number to a Civil Date. jd is the Julian Day Number. sg specifies the Day of Calendar Reform.

Returns the corresponding [year, month, day_of_month] as a three-element array.



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# File 'lib/date.rb', line 405

def self.jd_to_civil(jd, sg=GREGORIAN)
  if julian?(jd, sg)
    a = jd
  else
    x = ((jd - 1867216.25) / 36524.25).floor
    a = jd + 1 + x - (x / 4.0).floor
  end
  b = a + 1524
  c = ((b - 122.1) / 365.25).floor
  d = (365.25 * c).floor
  e = ((b - d) / 30.6001).floor
  dom = b - d - (30.6001 * e).floor
  if e <= 13
    m = e - 1
    y = c - 4716
  else
    m = e - 13
    y = c - 4715
  end
  return y, m, dom
end

.jd_to_commercial(jd, sg = GREGORIAN) ⇒ Object

Convert a Julian Day Number to a Commercial Date

jd is the Julian Day Number to convert. sg specifies the Day of Calendar Reform.

Returns the corresponding Commercial Date as [commercial_year, week_of_year, day_of_week]



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# File 'lib/date.rb', line 446

def self.jd_to_commercial(jd, sg=GREGORIAN)
  ns = fix_style(jd, sg)
  a = jd_to_civil(jd - 3, ns)[0]
  y = if jd >= commercial_to_jd(a + 1, 1, 1, ns) then a + 1 else a end
  w = 1 + ((jd - commercial_to_jd(y, 1, 1, ns)) / 7).floor
  d = (jd + 1) % 7
  d = 7 if d == 0
  return y, w, d
end

.jd_to_ld(jd) ⇒ Object

Convert a Julian Day Number to the number of days since the adoption of the Gregorian Calendar (in Italy).



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# File 'lib/date.rb', line 529

def self.jd_to_ld(jd) jd - 2299160 end

.jd_to_mjd(jd) ⇒ Object

Convert a Julian Day Number to a Modified Julian Day Number.



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# File 'lib/date.rb', line 521

def self.jd_to_mjd(jd) jd - 2400001 end

.jd_to_ordinal(jd, sg = GREGORIAN) ⇒ Object

Convert a Julian Day Number to an Ordinal Date.

jd is the Julian Day Number to convert. sg specifies the Day of Calendar Reform.

Returns the corresponding Ordinal Date as [year, day_of_year]



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# File 'lib/date.rb', line 372

def self.jd_to_ordinal(jd, sg=GREGORIAN)
  y = jd_to_civil(jd, sg)[0]
  doy = jd - civil_to_jd(y - 1, 12, 31, fix_style(jd, sg))
  return y, doy
end

.jd_to_wday(jd) ⇒ Object

Convert a Julian Day Number to the day of the week.

Sunday is day-of-week 0; Saturday is day-of-week 6.



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# File 'lib/date.rb', line 534

def self.jd_to_wday(jd) (jd + 1) % 7 end

.julian?(jd, sg) ⇒ Boolean

Does a given Julian Day Number fall inside the old-style (Julian) calendar?

jd is the Julian Day Number in question. sg may be Date::GREGORIAN, in which case the answer is false; it may be Date::JULIAN, in which case the answer is true; or it may a number representing the Day of Calendar Reform. Date::ENGLAND and Date::ITALY are two possible such days.

Returns:

  • (Boolean) 


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# File 'lib/date.rb', line 327

def self.julian? (jd, sg)
  case sg
  when Numeric
    jd < sg
  else
    if $VERBOSE
	warn("#{caller.shift.sub(/:in .*/, '')}: " \
"warning: do not use non-numerical object as julian day number anymore")
    end
    not sg
  end
end

.julian_leap?(y) ⇒ Boolean

Is a year a leap year in the Julian calendar?

All years divisible by 4 are leap years in the Julian calendar.

Returns:

  • (Boolean) 


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# File 'lib/date.rb', line 539

def self.julian_leap? (y) y % 4 == 0 end

.ld_to_jd(ld) ⇒ Object

Convert a count of the number of days since the adoption of the Gregorian Calendar (in Italy) to a Julian Day Number.



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# File 'lib/date.rb', line 525

def self.ld_to_jd(ld) ld + 2299160 end

.mjd_to_jd(mjd) ⇒ Object

Convert a Modified Julian Day Number to a Julian Day Number.



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# File 'lib/date.rb', line 517

def self.mjd_to_jd(mjd) mjd + 2400001 end

.new ⇒ Object Also known as: new!

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.



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# File 'lib/date.rb', line 732

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

.once(*ids) ⇒ Object

:nodoc:



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# File 'lib/date.rb', line 980

def once(*ids) # :nodoc:
  for id in ids
	module_eval <<-"end;"
	  alias_method :__#{id.to_i}__, :#{id.to_s}
	  private :__#{id.to_i}__
	  def #{id.to_s}(*args, &block)
 (@__#{id.to_i}__ ||= [__#{id.to_i}__(*args, &block)])[0]
	  end
	end;
  end
end

.ordinal(y = -4712,, d = 1, sg = ITALY) ⇒ Object

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.



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# File 'lib/date.rb', line 705

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

.ordinal_to_jd(y, d, sg = GREGORIAN) ⇒ Object

Convert an Ordinal Date to a Julian Day Number.

y and d are the year and day-of-year to convert. sg specifies the Day of Calendar Reform.

Returns the corresponding Julian Day Number.



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# File 'lib/date.rb', line 361

def self.ordinal_to_jd(y, d, sg=GREGORIAN)
  civil_to_jd(y, 1, d, sg)
end

.parse(str = '-4712-01-01', comp = false, sg = ITALY) ⇒ Object

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.



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# File 'lib/date.rb', line 973

def self.parse(str='-4712-01-01', comp=false, sg=ITALY)
  elem = _parse(str, comp)
  new_by_frags(elem, sg)
end

.strptime(str = '-4712-01-01', fmt = '%F', sg = ITALY) ⇒ Object

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.



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# File 'lib/date.rb', line 953

def self.strptime(str='-4712-01-01', fmt='%F', sg=ITALY)
  elem = _strptime(str, fmt)
  new_by_frags(elem, sg)
end

.time_to_day_fraction(h, min, s) ⇒ Object

Convert an h hour, min minutes, s seconds period to a fractional day.



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# File 'lib/date.rb', line 503

def self.time_to_day_fraction(h, min, s)
  h.to_r/24 + min.to_r/1440 + s.to_r/86400
end

.today(sg = ITALY) ⇒ Object

Create a new Date object representing today.

sg specifies the Day of Calendar Reform.



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# File 'lib/date.rb', line 1622

def self.today(sg=ITALY) Time.now.__send__(:to_date)    .new_start(sg) end

.valid_civil?(y, m, d, sg = ITALY) ⇒ Boolean Also known as: valid_date?

Do year y, month m, and day-of-month d make a valid Civil Date? Returns the corresponding Julian Day Number if they do, nil if they don't.

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. A date falling in the period skipped in the Day of Calendar Reform adjustment is not valid.

sg specifies the Day of Calendar Reform.

Returns:

  • (Boolean) 


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# File 'lib/date.rb', line 595

def self.valid_civil? (y, m, d, sg=ITALY)
  if m < 0
    m += 13
  end
  if d < 0
    ny, nm = (y * 12 + m).divmod(12)
    nm,    = (nm + 1).divmod(1)
    jd = civil_to_jd(ny, nm, d + 1, sg)
    ns = fix_style(jd, sg)
    return unless [y, m] == jd_to_civil(jd, sg)[0..1]
    return unless [ny, nm, 1] == jd_to_civil(jd - d, ns)
  else
    jd = civil_to_jd(y, m, d, sg)
    return unless [y, m, d] == jd_to_civil(jd, sg)
  end
  jd
end

.valid_commercial?(y, w, d, sg = ITALY) ⇒ Boolean

Do year y, week-of-year w, and day-of-week d make a valid Commercial Date? Returns the corresponding Julian Day Number if they do, nil if they don't.

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. A date falling in the period skipped in the Day of Calendar Reform adjustment is not valid.

sg specifies the Day of Calendar Reform.

Returns:

  • (Boolean) 


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# File 'lib/date.rb', line 629

def self.valid_commercial? (y, w, d, sg=ITALY)
  if d < 0
    d += 8
  end
  if w < 0
    ny, nw, nd =
	jd_to_commercial(commercial_to_jd(y + 1, 1, 1) + w * 7)
    return unless ny == y
    w = nw
  end
  jd = commercial_to_jd(y, w, d)
  return unless gregorian?(jd, sg)
  return unless [y, w, d] == jd_to_commercial(jd)
  jd
end

.valid_jd?(jd, sg = ITALY) ⇒ Boolean

Is jd a valid Julian Day Number?

If it is, returns it. In fact, any value is treated as a valid Julian Day Number.

Returns:

  • (Boolean) 


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# File 'lib/date.rb', line 554

def self.valid_jd? (jd, sg=ITALY) jd end

.valid_ordinal?(y, d, sg = ITALY) ⇒ Boolean

Do the year y and day-of-year d make a valid Ordinal Date? Returns the corresponding Julian Day Number if they do, or nil if they don't.

d can be a negative number, in which case it counts backwards from the end of the year (-1 being the last day of the year). No year wraparound is performed, however, so valid values of d are -365 .. -1, 1 .. 365 on a non-leap-year, -366 .. -1, 1 .. 366 on a leap year. A date falling in the period skipped in the Day of Calendar Reform adjustment is not valid.

sg specifies the Day of Calendar Reform.

Returns:

  • (Boolean) 


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# File 'lib/date.rb', line 569

def self.valid_ordinal? (y, d, sg=ITALY)
  if d < 0
    ny, = (y + 1).divmod(1)
    jd = ordinal_to_jd(ny, d + 1, sg)
    ns = fix_style(jd, sg)
    return unless [y] == jd_to_ordinal(jd, sg)[0..0]
    return unless [ny, 1] == jd_to_ordinal(jd - d, ns)
  else
    jd = ordinal_to_jd(y, d, sg)
    return unless [y, d] == jd_to_ordinal(jd, sg)
  end
  jd
end

.valid_time?(h, min, s) ⇒ Boolean

Do hour h, minute min, and second s constitute a valid time?

If they do, returns their value as a fraction of a day. If not, returns nil.

The 24-hour clock is used. Negative values of h, min, and sec are treating as counting backwards from the end of the next larger unit (e.g. a min of -2 is treated as 58). No wraparound is performed.

Returns:

  • (Boolean) 


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# File 'lib/date.rb', line 672

def self.valid_time? (h, min, s)
  h   += 24 if h   < 0
  min += 60 if min < 0
  s   += 60 if s   < 0
  return unless ((0..23) === h &&
   (0..59) === min &&
   (0..59) === s) ||
  (24 == h &&
    0 == min &&
    0 == s)
  time_to_day_fraction(h, min, s)
end

.zone_to_diff(zone) ⇒ Object

:nodoc:



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# File 'lib/date/format.rb', line 1018

def self.zone_to_diff(zone) # :nodoc:
  zone = zone.downcase
  if zone.sub!(/\s+(standard|daylight)\s+time\z/, '')
    dst = $1 == 'daylight'
  else
    dst = zone.sub!(/\s+dst\z/, '')
  end
  if Format::ZONES.include?(zone)
    offset = Format::ZONES[zone]
    offset += 3600 if dst
  elsif zone.sub!(/\A(?:gmt|utc?)?([-+])/, '')
    sign = $1
    if zone.include?(':')
	hour, min, sec, = zone.split(':')
    elsif zone.include?(',') || zone.include?('.')
	hour, fr, = zone.split(/[,.]/)
	min = fr.to_i.to_r / (10**fr.size) * 60
    else
	case zone.size
	when 3
 hour = zone[0,1]
 min = zone[1,2]
	else
 hour = zone[0,2]
 min = zone[2,2]
 sec = zone[4,2]
	end
    end
    offset = hour.to_i * 3600 + min.to_i * 60 + sec.to_i
    offset *= -1 if sign == '-'
  end
  offset
end

Instance Method Details

#+(n) ⇒ Object

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.

Raises:

  • (TypeError) 


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# File 'lib/date.rb', line 1200

def + (n)
  case n
  when Numeric; return self.class.new!(@ajd + n, @of, @sg)
  end
  raise TypeError, 'expected numeric'
end

#-(x) ⇒ Object

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.

Raises:

  • (TypeError) 


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# File 'lib/date.rb', line 1215

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

#<<(n) ⇒ Object

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.



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# File 'lib/date.rb', line 1286

def << (n) self >> -n end

#<=>(other) ⇒ Object

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.



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# File 'lib/date.rb', line 1234

def <=> (other)
  case other
  when Numeric; return @ajd <=> other
  when Date;    return @ajd <=> other.ajd
  end
  nil
end

#===(other) ⇒ Object

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.



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# File 'lib/date.rb', line 1248

def === (other)
  case other
  when Numeric; return jd == other
  when Date;    return jd == other.jd
  end
  false
end

#>>(n) ⇒ Object

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.



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# File 'lib/date.rb', line 1272

def >> (n)
  y, m = (year * 12 + (mon - 1) + n).divmod(12)
  m,   = (m + 1)                    .divmod(1)
  d = mday
  d -= 1 until jd2 = self.class.valid_civil?(y, m, d, fix_style)
  self + (jd2 - jd)
end

#_dump(limit) ⇒ Object

Dump to Marshal format.



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# File 'lib/date.rb', line 1346

def _dump(limit) Marshal.dump([@ajd, @of, @sg], -1) end

#ajd ⇒ Object

Get the date as an Astronomical Julian Day Number.



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# File 'lib/date.rb', line 1018

def ajd() @ajd end

#amjd ⇒ Object

Get the date as an Astronomical Modified Julian Day Number.



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# File 'lib/date.rb', line 1021

def amjd() self.class.ajd_to_amjd(@ajd) end

#asctime ⇒ Object Also known as: ctime

alias_method :format, :strftime



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# File 'lib/date/format.rb', line 336

def asctime() strftime('%c') end

#cwday ⇒ Object

Get the commercial day of the week of this date. Monday is commercial day-of-week 1; Sunday is commercial day-of-week 7.



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# File 'lib/date.rb', line 1114

def cwday() commercial[2] end

#cweek ⇒ Object

Get the commercial week of the year of this date.



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# File 'lib/date.rb', line 1110

def cweek() commercial[1] end

#cwyear ⇒ Object

Get the commercial year of this date. See Commercial Date in the introduction for how this differs from the normal year.



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# File 'lib/date.rb', line 1107

def cwyear() commercial[0] end

#day_fraction ⇒ Object

Get any fractional day part of the date.



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# File 'lib/date.rb', line 1029

def day_fraction() self.class.ajd_to_jd(@ajd, @of)[1] end

#downto(min, &block) ⇒ Object

Step backward one day at a time until we reach min (inclusive), yielding each date as we go.



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# File 'lib/date.rb', line 1325

def downto(min, &block) # :yield: date
  step(min, -1, &block)
end

#england ⇒ Object

Create a copy of this Date object that uses the English/Colonial Day of Calendar Reform.



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# File 'lib/date.rb', line 1170

def england() new_start(self.class::ENGLAND) end

#eql?(other) ⇒ Boolean

Is this Date equal to other?

other must both be a Date object, and represent the same date.

Returns:

  • (Boolean) 


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# File 'lib/date.rb', line 1332

def eql? (other) Date === other && self == other end

#gregorian ⇒ Object

Create a copy of this Date object that always uses the Gregorian Calendar.



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# File 'lib/date.rb', line 1178

def gregorian() new_start(self.class::GREGORIAN) end

#gregorian? ⇒ Boolean

Is the current date new-style (Gregorian Calendar)?

Returns:

  • (Boolean) 


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# File 'lib/date.rb', line 1138

def gregorian? () self.class.gregorian?(jd, @sg) end

#hash ⇒ Object

Calculate a hash value for this date.



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# File 'lib/date.rb', line 1335

def hash() @ajd.hash end

#inspect ⇒ Object

Return internal object state as a programmer-readable string.



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# File 'lib/date.rb', line 1338

def inspect() format('#<%s: %s,%s,%s>', self.class, @ajd, @of, @sg) end

#italy ⇒ Object

Create a copy of this Date object that uses the Italian/Catholic Day of Calendar Reform.



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# File 'lib/date.rb', line 1166

def italy() new_start(self.class::ITALY) end

#jd ⇒ Object

Get the date as a Julian Day Number.



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# File 'lib/date.rb', line 1026

def jd() self.class.ajd_to_jd(@ajd, @of)[0] end

#julian ⇒ Object

Create a copy of this Date object that always uses the Julian Calendar.



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# File 'lib/date.rb', line 1174

def julian() new_start(self.class::JULIAN) end

#julian? ⇒ Boolean

Is the current date old-style (Julian Calendar)?

Returns:

  • (Boolean) 


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# File 'lib/date.rb', line 1135

def julian? () self.class.julian?(jd, @sg) end

#ld ⇒ Object

Get the date as the number of days since the Day of Calendar Reform (in Italy and the Catholic countries).



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# File 'lib/date.rb', line 1036

def ld() self.class.jd_to_ld(jd) end

#leap? ⇒ Boolean

Is this a leap year?

Returns:

  • (Boolean) 


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# File 'lib/date.rb', line 1151

def leap?
  self.class.jd_to_civil(self.class.civil_to_jd(year, 3, 1, fix_style) - 1,
     fix_style)[-1] == 29
end

#mday ⇒ Object Also known as: day

Get the day-of-the-month of this date.



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# File 'lib/date.rb', line 1069

def mday() civil[2] end

#mjd ⇒ Object

Get the date as a Modified Julian Day Number.



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# File 'lib/date.rb', line 1032

def mjd() self.class.jd_to_mjd(jd) end

#mon ⇒ Object Also known as: month

Get the month of this date.

January is month 1.



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# File 'lib/date.rb', line 1066

def mon() civil[1] end

#new_start(sg = self.class::ITALY) ⇒ Object

Create a copy of this Date object using a new Day of Calendar Reform.



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# File 'lib/date.rb', line 1162

def new_start(sg=self.class::ITALY) self.class.new!(@ajd, @of, sg) end

#next ⇒ Object Also known as: succ

Return a new Date one day after this one.



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# File 'lib/date.rb', line 1262

def next() next_day end

#start ⇒ Object

When is the Day of Calendar Reform for this Date object?



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# File 'lib/date.rb', line 1159

def start() @sg end

#step(limit, step = 1) ⇒ Object

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.



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# File 'lib/date.rb', line 1302

def step(limit, step=1) # :yield: date
=begin
  unless block_given?
    return to_enum(:step, limit, step)
  end
=end
  da = self
  op = %w(- <= >=)[step <=> 0]
  while da.__send__(op, limit)
    yield da
    da += step
  end
  self
end

#strftime(fmt = '%F') ⇒ Object 



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# File 'lib/date/format.rb', line 200

def strftime(fmt='%F')
  fmt.gsub(/%([-_0^#]+)?(\d+)?[EO]?(:{1,3}z|.)/m) do |m|
    f = {}
    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'; emit_sn((year / 100).floor, 2, f)
    when 'c'; emit_a(strftime('%a %b %e %H:%M:%S %Y'), 0, f)
    when 'D'; emit_a(strftime('%m/%d/%y'), 0, f)
    when 'd'; emit_n(mday, 2, f)
    when 'e'; 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'; emit_n(hour, 2, f)
    when 'h'; emit_ad(strftime('%b'), 0, f)
    when 'I'; emit_n((hour % 12).nonzero? || 12, 2, f)
    when 'j'; emit_n(yday, 3, f)
    when 'k'; emit_a(hour, 2, f)
    when 'L'
	emit_n((sec_fraction / (1.to_r/86400/(10**3))).round, 3, f)
    when 'l'; emit_a((hour % 12).nonzero? || 12, 2, f)
    when 'M'; emit_n(min, 2, f)
    when 'm'; emit_n(mon, 2, f)
    when 'N'
	emit_n((sec_fraction / (1.to_r/86400/(10**9))).round, 9, f)
    when 'n'; "\n"
    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'
	d = ajd - self.class.jd_to_ajd(self.class::UNIXEPOCH, 0)
	s = (d * 86400*10**3).to_i
	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'; emit_n(sec, 2, f)
    when 's'
	d = ajd - self.class.jd_to_ajd(self.class::UNIXEPOCH, 0)
	s = (d * 86400).to_i
	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'; "\t"
    when 'U', 'W'
	emit_n(if c == 'U' then wnum0 else wnum1 end, 2, f)
    when 'u'; emit_n(cwday, 1, f)
    when 'V'; emit_n(cweek, 2, f)
    when 'v'; emit_a(strftime('%e-%b-%Y'), 0, f)
    when 'w'; emit_n(wday, 1, f)
    when 'X'; emit_a(strftime('%H:%M:%S'), 0, f)
    when 'x'; emit_a(strftime('%m/%d/%y'), 0, f)
    when 'Y'; emit_sn(year, 4, f)
    when 'y'; 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
	hh, fr = fr.divmod(1.to_r/24)
	mm, fr = fr.divmod(1.to_r/1440)
	ss, fr = fr.divmod(1.to_r/86400)
	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)
    when '1'
	if $VERBOSE
 warn("warning: strftime: %1 is deprecated; forget this")
	end
	emit_n(jd, 1, f)
    when '2'
	if $VERBOSE
 warn("warning: strftime: %2 is deprecated; use '%Y-%j'")
	end
	emit_a(strftime('%Y-%j'), 0, f)
    when '3'
	if $VERBOSE
 warn("warning: strftime: %3 is deprecated; use '%F'")
	end
	emit_a(strftime('%F'), 0, f)
    else
	c
    end
  end
end

#to_s ⇒ Object

Return the date as a human-readable string.

The format used is YYYY-MM-DD.



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# File 'lib/date.rb', line 1343

def to_s() strftime end

#upto(max, &block) ⇒ Object

Step forward one day at a time until we reach max (inclusive), yielding each date as we go.



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# File 'lib/date.rb', line 1319

def upto(max, &block) # :yield: date
  step(max, +1, &block)
end

#wday ⇒ Object

Get the week day of this date. Sunday is day-of-week 0; Saturday is day-of-week 6.



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# File 'lib/date.rb', line 1118

def wday() self.class.jd_to_wday(jd) end

#yday ⇒ Object

Get the day-of-the-year of this date.

January 1 is day-of-the-year 1



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# File 'lib/date.rb', line 1061

def yday() ordinal[1] end

#year ⇒ Object

Get the year of this date.



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# File 'lib/date.rb', line 1056

def year() civil[0] end