# class DateTime

### Public Class Methods

civil_from_format(utc_or_local, year, month=1, day=1, hour=0, min=0, sec=0) click to toggle source

    # File lib/active_support/core_ext/date_time/conversions.rb, line 77
    def self.civil_from_format(utc_or_local, year, month=1, day=1, hour=0, min=0, sec=0)
      offset = utc_or_local.to_sym == :local ? local_offset : 0
      civil(year, month, day, hour, min, sec, offset)
    end

current() click to toggle source

Returns `Time.zone.now.to_datetime` when `Time.zone` or `config.time_zone` are set, otherwise returns `Time.now.to_datetime`.

    # File lib/active_support/core_ext/date_time/calculations.rb, line 11
    def current
      ::Time.zone ? ::Time.zone.now.to_datetime : ::Time.now.to_datetime
    end

local_offset() click to toggle source

DateTimes aren’t aware of DST rules, so use a consistent non-DST offset when creating a DateTime with an offset in the local zone

    # File lib/active_support/core_ext/date_time/calculations.rb, line 6
    def local_offset
      ::Time.local(2012).utc_offset.to_r / 86400
    end

### Public Instance Methods

<=>(other) click to toggle source

Layers additional behavior on DateTime#<=> so that Time and ActiveSupport::TimeWithZone instances can be compared with a DateTime

    # File lib/active_support/core_ext/date_time/calculations.rb, line 129
    def <=>(other)
      super other.to_datetime
    end

acts_like_date?() click to toggle source

Duck-types as a Date-like class. See Object#acts_like?.

    # File lib/active_support/core_ext/date_time/acts_like.rb, line 5
    def acts_like_date?
      true
    end

acts_like_time?() click to toggle source

Duck-types as a Time-like class. See Object#acts_like?.

    # File lib/active_support/core_ext/date_time/acts_like.rb, line 10
    def acts_like_time?
      true
    end

advance(options) click to toggle source

Uses Date to provide precise Time calculations for years, months, and days. The `options` parameter takes a hash with any of these keys: `:years`, `:months`, `:weeks`, `:days`, `:hours`, `:minutes`, `:seconds`.

    # File lib/active_support/core_ext/date_time/calculations.rb, line 51
    def advance(options)
      d = to_date.advance(options)
      datetime_advanced_by_date = change(:year => d.year, :month => d.month, :day => d.day)
      seconds_to_advance = (options[:seconds] || 0) + (options[:minutes] || 0) * 60 + (options[:hours] || 0) * 3600
      seconds_to_advance == 0 ? datetime_advanced_by_date : datetime_advanced_by_date.since(seconds_to_advance)
    end

ago(seconds) click to toggle source

Returns a new DateTime representing the time a number of seconds ago Do not use this method in combination with x.months, use months_ago instead!

    # File lib/active_support/core_ext/date_time/calculations.rb, line 60
    def ago(seconds)
      since(-seconds)
    end

at_beginning_of_day() click to toggle source
Alias for: beginning_of_day
at_midnight() click to toggle source
Alias for: beginning_of_day
beginning_of_day() click to toggle source

Returns a new DateTime representing the start of the day (0:00)

    # File lib/active_support/core_ext/date_time/calculations.rb, line 72
    def beginning_of_day
      change(:hour => 0)
    end

Also aliased as: midnight, at_midnight, at_beginning_of_day
change(options) click to toggle source

Returns a new DateTime where one or more of the elements have been changed according to the `options` parameter. The time options (hour, minute, sec) reset cascadingly, so if only the hour is passed, then minute and sec is set to 0. If the hour and minute is passed, then sec is set to 0.

    # File lib/active_support/core_ext/date_time/calculations.rb, line 34
    def change(options)
      ::DateTime.civil(
        options[:year]  || year,
        options[:month] || month,
        options[:day]   || day,
        options[:hour]  || hour,
        options[:min]   || (options[:hour] ? 0 : min),
        options[:sec]   || ((options[:hour] || options[:min]) ? 0 : sec),
        options[:offset]  || offset,
        options[:start]  || start
      )
    end

default_inspect() click to toggle source
Alias for: inspect
end_of_day() click to toggle source

Returns a new DateTime representing the end of the day (23:59:59)

    # File lib/active_support/core_ext/date_time/calculations.rb, line 80
    def end_of_day
      change(:hour => 23, :min => 59, :sec => 59)
    end

formatted_offset(colon = true, alternate_utc_string = nil) click to toggle source

Returns the `utc_offset` as an +HH:MM formatted string. Examples:

    datetime = DateTime.civil(2000, 1, 1, 0, 0, 0, Rational(-6, 24))
    datetime.formatted_offset         # => "-06:00"
    datetime.formatted_offset(false)  # => "-0600"

    # File lib/active_support/core_ext/date_time/conversions.rb, line 50
    def formatted_offset(colon = true, alternate_utc_string = nil)
      utc? && alternate_utc_string || ActiveSupport::TimeZone.seconds_to_utc_offset(utc_offset, colon)
    end

future?() click to toggle source

Tells whether the DateTime object’s datetime lies in the future

    # File lib/active_support/core_ext/date_time/calculations.rb, line 22
    def future?
      self > ::DateTime.current
    end

getutc() click to toggle source
Alias for: utc
in(seconds) click to toggle source
Alias for: since
in_time_zone(zone = ::Time.zone) click to toggle source

Returns the simultaneous time in `Time.zone`.

    Time.zone = 'Hawaii'             # => 'Hawaii'
    DateTime.new(2000).in_time_zone  # => Fri, 31 Dec 1999 14:00:00 HST -10:00

This method is similar to Time#localtime, except that it uses `Time.zone` as the local zone instead of the operating system’s time zone.

You can also pass in a TimeZone instance or string that identifies a TimeZone as an argument, and the conversion will be based on that zone instead of `Time.zone`.

    DateTime.new(2000).in_time_zone('Alaska')  # => Fri, 31 Dec 1999 15:00:00 AKST -09:00

    # File lib/active_support/core_ext/date_time/zones.rb, line 16
    def in_time_zone(zone = ::Time.zone)
      return self unless zone

      ActiveSupport::TimeWithZone.new(utc? ? self : getutc, ::Time.find_zone!(zone))
    end

inspect() click to toggle source
Also aliased as: default_inspect
Alias for: readable_inspect
midnight() click to toggle source
Alias for: beginning_of_day
past?() click to toggle source

Tells whether the DateTime object’s datetime lies in the past

    # File lib/active_support/core_ext/date_time/calculations.rb, line 17
    def past?
      self < ::DateTime.current
    end

readable_inspect() click to toggle source

Overrides the default inspect method with a human readable one, e.g., “Mon, 21 Feb 2005 14:30:00 +0000”.

    # File lib/active_support/core_ext/date_time/conversions.rb, line 55
    def readable_inspect
      to_s(:rfc822)
    end

Also aliased as: inspect
seconds_since_midnight() click to toggle source

Seconds since midnight: DateTime.now.#seconds_since_midnight

    # File lib/active_support/core_ext/date_time/calculations.rb, line 27
    def seconds_since_midnight
      sec + (min * 60) + (hour * 3600)
    end

since(seconds) click to toggle source

Returns a new DateTime representing the time a number of seconds since the instance time Do not use this method in combination with x.months, use months_since instead!

    # File lib/active_support/core_ext/date_time/calculations.rb, line 66
    def since(seconds)
      self + Rational(seconds.round, 86400)
    end

Also aliased as: in
to_date() click to toggle source

Converts self to a Ruby Date object; time portion is discarded.

    # File lib/active_support/core_ext/date_time/conversions.rb, line 62
    def to_date
      ::Date.new(year, month, day)
    end

to_datetime() click to toggle source

To be able to keep Times, Dates and DateTimes interchangeable on conversions.

    # File lib/active_support/core_ext/date_time/conversions.rb, line 73
    def to_datetime
      self
    end

to_default_s(format = :default) click to toggle source
Alias for: to_s
to_f() click to toggle source

Converts self to a floating-point number of seconds since the Unix epoch.

    # File lib/active_support/core_ext/date_time/conversions.rb, line 88
    def to_f
      seconds_since_unix_epoch.to_f
    end

to_formatted_s(format = :default) click to toggle source

Convert to a formatted string. See Time::DATE_FORMATS for predefined formats.

This method is aliased to `to_s`.

### Examples

    datetime = DateTime.civil(2007, 12, 4, 0, 0, 0, 0)   # => Tue, 04 Dec 2007 00:00:00 +0000

    datetime.to_formatted_s(:db)            # => "2007-12-04 00:00:00"
    datetime.to_s(:db)                      # => "2007-12-04 00:00:00"
    datetime.to_s(:number)                  # => "20071204000000"
    datetime.to_formatted_s(:short)         # => "04 Dec 00:00"
    datetime.to_formatted_s(:long)          # => "December 04, 2007 00:00"
    datetime.to_formatted_s(:long_ordinal)  # => "December 4th, 2007 00:00"
    datetime.to_formatted_s(:rfc822)        # => "Tue, 04 Dec 2007 00:00:00 +0000"

## Adding your own datetime formats to #to_formatted_s

DateTime formats are shared with Time. You can add your own to the Time::DATE_FORMATS hash. Use the format name as the hash key and either a strftime string or Proc instance that takes a time or datetime argument as the value.

    # config/initializers/time_formats.rb
    Time::DATE_FORMATS[:month_and_year] = "%B %Y"
    Time::DATE_FORMATS[:short_ordinal] = lambda { |time| time.strftime("%B #{time.day.ordinalize}") }

    # File lib/active_support/core_ext/date_time/conversions.rb, line 35
    def to_formatted_s(format = :default)
      if formatter = ::Time::DATE_FORMATS[format]
        formatter.respond_to?(:call) ? formatter.call(self).to_s : strftime(formatter)
      else
        to_default_s
      end
    end

Also aliased as: to_s
to_i() click to toggle source

Converts self to an integer number of seconds since the Unix epoch.

    # File lib/active_support/core_ext/date_time/conversions.rb, line 93
    def to_i
      seconds_since_unix_epoch.to_i
    end

to_s(format = :default) click to toggle source
Also aliased as: to_default_s
Alias for: to_formatted_s
to_time() click to toggle source

Attempts to convert self to a Ruby Time object; returns self if out of range of Ruby Time class. If self has an offset other than 0, self will just be returned unaltered, since there’s no clean way to map it to a Time.

    # File lib/active_support/core_ext/date_time/conversions.rb, line 68
    def to_time
      self.offset == 0 ? ::Time.utc_time(year, month, day, hour, min, sec, sec_fraction * (RUBY_VERSION < '1.9' ? 86400000000 : 1000000)) : self
    end

utc() click to toggle source

Adjusts DateTime to UTC by adding its offset value; offset is set to 0

Example:

    DateTime.civil(2005, 2, 21, 10, 11, 12, Rational(-6, 24))       # => Mon, 21 Feb 2005 10:11:12 -0600
    DateTime.civil(2005, 2, 21, 10, 11, 12, Rational(-6, 24)).utc   # => Mon, 21 Feb 2005 16:11:12 +0000

    # File lib/active_support/core_ext/date_time/calculations.rb, line 113
    def utc
      new_offset(0)
    end

Also aliased as: getutc
utc?() click to toggle source

Returns true if offset == 0

    # File lib/active_support/core_ext/date_time/calculations.rb, line 119
    def utc?
      offset == 0
    end

utc_offset() click to toggle source

Returns the offset value in seconds

    # File lib/active_support/core_ext/date_time/calculations.rb, line 124
    def utc_offset
      (offset * 86400).to_i
    end

xmlschema() click to toggle source

Converts datetime to an appropriate format for use in XML.

    # File lib/active_support/core_ext/date_time/conversions.rb, line 83
    def xmlschema
      strftime("%Y-%m-%dT%H:%M:%S%Z")
    end