date2 - An alternative date class

Date

Super Class

Object

Included Modules

Comparable

Class Methods

civil([year[, mon[, mday[, start]]]])
new([year[, mon[, mday[, start]]]])

Creates a date object denoting the given 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 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 (reverse order when negative). They should not be zero.

The last argument should be a Julian day number which denotes the first day of the Gregorian calendar. You can also give true which mean the proleptic Gregorian calendar, and false which mean the proleptic Julian calendar. Default is Date::ITALY (October 15, 1582).

See also jd.

commercial([cwyear[, cweek[, cwday[, start]]]])

Creates a date object denoting the given week date.

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.

The week and the day of week should be a negative or a positive number (reverse order when negative). They should not be zero.

This method does not accept dates before the day of calendar reform.

See also jd and new.

jd ([jd[, start]])

Creates a date object denoting the given 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 class, some important methods do not accept negative Julian day numbers.

See also new.

ordinal([year[, yday[, start]]])

Creates a date object denoting the given ordinal date.

The ordinal date is a particular day of a calendar year identified by its ordinal number within the year.

The day of year should be a negative or a positive number (reverse order when negative). It should not be zero.

See also jd and new.

parse(str[, complete[, start]])

Parses the given representation of dates and times, and creates a date object.

If the optional second argument is true and the detected year is in the range 0 to 99, considers the year a 2-digit form and makes it full. Default is false.

_parse is also available. This method is similar to parse, but returns a hash which contain detected elements, not creates a date object.

strptime(str[, format[, start]])

Parses the given representation of dates and times with the given template, and creates a date object.

_strptime is also available. This method is similar to strptime, but returns a hash which contain detected elements, not creates a date object.

See also strptime(3) and strftime.

today([start])

Creates a date object denoting the present day.

valid_civil? (year, mon, mday[, start])
exist? (year, mon, mday[, start])

Returns a Julian day number if the given calendar date is valid, and nil if not.

See also jd and civil.

valid_commercial? (cwyear, cweek, cwday[, start])

Returns a Julian day number if the given week date is valid, and nil if not.

See also jd and commercial.

valid_jd? (jd[, start])

Just returns the first argument immediately.

It's nonsense, but is for symmetry.

See also jd.

valid_ordinal? (year, yday[, start])

Returns a Julian day number if the given ordinal date is valid, and nil if not.

See also jd and ordinal.

Methods

self + n

Returns a date object pointing n days after self. The n should be a numeric value.

self - x

Returns the difference between the two dates if the x is a date object. If the x is a numeric value, it returns a date object pointing x days before self.

self << n

Returns a date object pointing n months before self. The n should be a numeric value.

self <=> other

Compares the two dates and returns -1, zero or 1. The other should be a date object or a numeric value as a Julian day number.

self === other

Returns true if they are the same day.

self >> n

Returns a date object pointing n months after self. The n should be a numeric value.

asctime
ctime

Returns a string in asctime(3) format (but without "\n\0" at the end).

cwday

Returns the day of calendar week (1-7, Monday is 1).

cweek

Returns the calendar week number (1-53).

cwyear

Returns the calendar week based year.

downto(min){|date| ...}

This method is equivalent to step(min, -1){|date| ...}.

england

This method is equivalent to new_start(Date::ENGLAND).

gregorian

This method is equivalent to new_start(Date::GREGORIAN).

italy

This method is equivalent to new_start(Date::ITALY).

jd

Returns the Julian day number (as noon).

julian

This method is equivalent to new_start(Date::JULIAN).

leap?

Returns true if the year is a leap year.

mday
day

Returns the day of month (1-31).

mjd

Returns the modified Julian day number (as noon).

the modified Julian day number is in elapsed days since midnight (Coordinated universal time) on November 17, 1858 CE (in the Gregorian calendar).

mon
month

Returns the month (1-12).

new_start([start])

Duplicates self and resets the its first day of the Gregorian calendar. Default is Date::ITALY (October 15, 1582).

See also new.

start

Returns a Julian day number denoting the first day of the Gregorian calendar.

See also new.

step(limit, step){|date| ...}

Iterates evaluation of the given block, which takes a date object. The limit should be a date object, and the step should be a nonzero value.

strftime([format])

Formats the date with the given template. The following conversion specifications are supported:

%A, %a, %B, %b, %C, %c, %D, %d, %e, %F, %G, %g, %H, %h, %I, %j, %k, %l, %M, %m, %n, %P, %p, %R, %r, %S, %s, %T, %t, %U, %u, %V, %v, %W, %w, %X, %x, %Y, %y, %Z, %z, %%, %+

See also strftime(3) and strptime.

succ
next

Returns a date object denoting the following day.

to_s

Returns a string in an ISO 8601 format (This method doesn't use the expanded representations).

upto(max){|date| ...}

This method is equivalent to step(max, 1){|date| ...}.

wday

Returns the day of week (0-6, Sunday is zero).

yday

Returns the day of year (1-366).

year

Returns the year.

DateTime

Super Class

Date

Class Methods

civil([year[, mon[, mday[, hour[, min[, sec[, offset[, start]]]]]]]])
new([year[, mon[, mday[, hour[, min[, sec[, offset[, start]]]]]]]])

Creates a date-time object denoting the given calendar date.

commercial([cwyear[, cweek[, cwday[, hour[, min[, sec[, offset[, start]]]]]]]])

Creates a date-time object denoting the given week date.

jd([jd[, hour[, min[, sec[, offset[, start]]]]]])

Creates a date-time object denoting the given Julian day number.

now([start])

Creates a date-time object denoting the present time.

ordinal([year[, yday[, hour[, min[, sec[, offset[, start]]]]]]])

Creates a date-time object denoting the given ordinal date.

Methods

hour

Returns the hour (0-23).

min

Returns the minute (0-59).

new_offset([offset])

Duplicates self and resets the its offset. Default is zero (UTC).

See also new.

offset

Returns the offset.

sec

Returns the second (0-59).

zone

Returns the timezone.

date2/holiday - determination of secular and religious holidays

Date

Class Methods

gregorian_easter(year[, start])
easter(year[, start])

Returns a date object denoting the Easter sunday in the given Gregorian year.

julian_easter(year[, start])

Returns a date object denoting the Easter sunday in the given Julian year.

nth_kday(n, k, year, mon[, start])

Returns a date object denoting the given Nth (-5 to 5, except zero) Kday (0-6) in the given month of year.

Methods

easter?

Returns true if the day is an Easter sunday.

national_holiday?

Returns true if the day is a Japanese national holiday.

nth_kday?(n, k)

Returns true if the day is an Nth (-5 to 5, except zero) Kday (0-6).

date2/qholiday - determination of old Japanese national holidays

Date

This provides some methods to determine old Japanese national holidays. This is still experimental.

parsedate2 - parse date and time

ParseDate

Module Functions

parsedate(str[, complete])

Parses the given representation of dates and times, and returns an array which contain detected elements (year, month, day of month, hour, minute, second, timezone and day of week).

If the optional second argument is true and the detected year is in the range 0 to 99, considers the year a 2-digit form and makes it full. Default is false.

See also Date.parse.