class DateTime - activesupport-4.2.3 Documentation

# 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

Returns DateTime with local offset for given year if format is local else offset is zero.

    DateTime.civil_from_format :local, 2012
    # => Sun, 01 Jan 2012 00:00:00 +0300
    DateTime.civil_from_format :local, 2012, 12, 17
    # => Mon, 17 Dec 2012 00:00:00 +0000

    # File lib/active_support/core_ext/date_time/conversions.rb, line 65
    def self.civil_from_format(utc_or_local, year, month=1, day=1, hour=0, min=0, sec=0)
      if utc_or_local.to_sym == :local
        offset = ::Time.local(year, month, day).utc_offset.to_r / 86400
      else
        offset = 0
      end
      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 8
    def current
      ::Time.zone ? ::Time.zone.now.to_datetime : ::Time.now.to_datetime
    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.

Calls superclass method

    # File lib/active_support/core_ext/date_time/calculations.rb, line 163
    def <=>(other)
      if other.kind_of?(Infinity)
        super
      elsif other.respond_to? :to_datetime
        super other.to_datetime rescue nil
      else
        nil
      end
    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 6
    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 11
    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 55
    def advance(options)
      unless options[:weeks].nil?
        options[:weeks], partial_weeks = options[:weeks].divmod(1)
        options[:days] = options.fetch(:days, 0) + 7 * partial_weeks
      end

      unless options[:days].nil?
        options[:days], partial_days = options[:days].divmod(1)
        options[:hours] = options.fetch(:hours, 0) + 24 * partial_days
      end

      d = to_date.advance(options)
      datetime_advanced_by_date = change(:year => d.year, :month => d.month, :day => d.day)
      seconds_to_advance =        options.fetch(:seconds, 0) +
        options.fetch(:minutes, 0) * 60 +
        options.fetch(:hours, 0) * 3600

      if seconds_to_advance.zero?
        datetime_advanced_by_date
      else
        datetime_advanced_by_date.since(seconds_to_advance)
      end
    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 82
    def ago(seconds)
      since(-seconds)
    end

at_beginning_of_day()
Alias for: beginning_of_day
at_beginning_of_hour()
Alias for: beginning_of_hour
at_beginning_of_minute()
Alias for: beginning_of_minute
at_end_of_day()
Alias for: end_of_day
at_end_of_hour()
Alias for: end_of_hour
at_end_of_minute()
Alias for: end_of_minute
at_midday()
Alias for: middle_of_day
at_middle_of_day()
Alias for: middle_of_day
at_midnight()
Alias for: beginning_of_day
at_noon()
Alias for: middle_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 95
    def beginning_of_day
      change(:hour => 0)
    end

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

Returns a new DateTime representing the start of the hour (hh:00:00).

    # File lib/active_support/core_ext/date_time/calculations.rb, line 119
    def beginning_of_hour
      change(:min => 0)
    end

Also aliased as: at_beginning_of_hour
beginning_of_minute() click to toggle source

Returns a new DateTime representing the start of the minute (hh:mm:00).

    # File lib/active_support/core_ext/date_time/calculations.rb, line 131
    def beginning_of_minute
      change(:sec => 0)
    end

Also aliased as: at_beginning_of_minute
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`, `:min`, `: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. The `options` parameter takes a hash with any of these keys: `:year`, `:month`, `:day`, `:hour`, `:min`, `:sec`, `:offset`, `:start`.

    DateTime.new(2012, 8, 29, 22, 35, 0).change(day: 1)              # => DateTime.new(2012, 8, 1, 22, 35, 0)
    DateTime.new(2012, 8, 29, 22, 35, 0).change(year: 1981, day: 1)  # => DateTime.new(1981, 8, 1, 22, 35, 0)
    DateTime.new(2012, 8, 29, 22, 35, 0).change(year: 1981, hour: 0) # => DateTime.new(1981, 8, 29, 0, 0, 0)

    # File lib/active_support/core_ext/date_time/calculations.rb, line 38
    def change(options)
      ::DateTime.civil(
        options.fetch(:year, year),
        options.fetch(:month, month),
        options.fetch(:day, day),
        options.fetch(:hour, hour),
        options.fetch(:min, options[:hour] ? 0 : min),
        options.fetch(:sec, (options[:hour] || options[:min]) ? 0 : sec + sec_fraction),
        options.fetch(:offset, offset),
        options.fetch(:start, start)
      )
    end

default_inspect()
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 113
    def end_of_day
      change(:hour => 23, :min => 59, :sec => 59)
    end

Also aliased as: at_end_of_day
end_of_hour() click to toggle source

Returns a new DateTime representing the end of the hour (hh:59:59).

    # File lib/active_support/core_ext/date_time/calculations.rb, line 125
    def end_of_hour
      change(:min => 59, :sec => 59)
    end

Also aliased as: at_end_of_hour
end_of_minute() click to toggle source

Returns a new DateTime representing the end of the minute (hh:mm:59).

    # File lib/active_support/core_ext/date_time/calculations.rb, line 137
    def end_of_minute
      change(:sec => 59)
    end

Also aliased as: at_end_of_minute
formatted_offset(colon = true, alternate_utc_string = nil) click to toggle source

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 47
    def formatted_offset(colon = true, alternate_utc_string = nil)
      utc? && alternate_utc_string || ActiveSupport::TimeZone.seconds_to_utc_offset(utc_offset, colon)
    end

getutc()
Alias for: utc
in(seconds)
Alias for: since
inspect()
Also aliased as: default_inspect
Alias for: readable_inspect
midday()
Alias for: middle_of_day
middle_of_day() click to toggle source

Returns a new DateTime representing the middle of the day (12:00)

    # File lib/active_support/core_ext/date_time/calculations.rb, line 103
    def middle_of_day
      change(:hour => 12)
    end

Also aliased as: midday, noon, at_midday, at_noon, at_middle_of_day
midnight()
Alias for: beginning_of_day
noon()
Alias for: middle_of_day
nsec() click to toggle source

Returns the fraction of a second as nanoseconds

    # File lib/active_support/core_ext/date_time/conversions.rb, line 90
    def nsec
      (sec_fraction * 1_000_000_000).to_i
    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 52
    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 14
    def seconds_since_midnight
      sec + (min * 60) + (hour * 3600)
    end

seconds_until_end_of_day() click to toggle source

Returns the number of seconds until 23:59:59.

    DateTime.new(2012, 8, 29,  0,  0,  0).seconds_until_end_of_day # => 86399
    DateTime.new(2012, 8, 29, 12, 34, 56).seconds_until_end_of_day # => 41103
    DateTime.new(2012, 8, 29, 23, 59, 59).seconds_until_end_of_day # => 0

    # File lib/active_support/core_ext/date_time/calculations.rb, line 23
    def seconds_until_end_of_day
      end_of_day.to_i - to_i
    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 89
    def since(seconds)
      self + Rational(seconds.round, 86400)
    end

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

Converts `self` to a floating-point number of seconds, including fractional microseconds, since the Unix epoch.

    # File lib/active_support/core_ext/date_time/conversions.rb, line 75
    def to_f
      seconds_since_unix_epoch.to_f + sec_fraction
    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"
    datetime.to_formatted_s(:iso8601)       # => "2007-12-04T00:00:00+00:00"

## 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 33
    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 80
    def to_i
      seconds_since_unix_epoch.to_i
    end

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

Returns the fraction of a second as microseconds

    # File lib/active_support/core_ext/date_time/conversions.rb, line 85
    def usec
      (sec_fraction * 1_000_000).to_i
    end

utc() click to toggle source

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

    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 146
    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 152
    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 157
    def utc_offset
      (offset * 86400).to_i
    end

### Private Instance Methods

offset_in_seconds() click to toggle source

    # File lib/active_support/core_ext/date_time/conversions.rb, line 96
    def offset_in_seconds
      (offset * 86400).to_i
    end

seconds_since_unix_epoch() click to toggle source

    # File lib/active_support/core_ext/date_time/conversions.rb, line 100
    def seconds_since_unix_epoch
      (jd - 2440588) * 86400 - offset_in_seconds + seconds_since_midnight
    end