Methods
#
A
B
C
D
E
F
I
L
M
N
P
S
T
U
W
Y
Z
Constants
COMMON_YEAR_DAYS_IN_MONTH = [nil, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31]
 
DAYS_INTO_WEEK = { :monday => 0, :tuesday => 1, :wednesday => 2, :thursday => 3, :friday => 4, :saturday => 5, :sunday => 6 }
 
DATE_FORMATS = { :db => "%Y-%m-%d %H:%M:%S", :number => "%Y%m%d%H%M%S", :time => "%H:%M", :short => "%d %b %H:%M", :long => "%B %d, %Y %H:%M", :long_ordinal => lambda { |time| time.strftime("%B #{ActiveSupport::Inflector.ordinalize(time.day)}, %Y %H:%M") }, :rfc822 => lambda { |time| time.strftime("%a, %d %b %Y %H:%M:%S #{time.formatted_offset(false)}") } }
 
Attributes
[RW] zone_default
Class Public methods
===(other)

Overriding case equality method so that it returns true for ActiveSupport::TimeWithZone instances

# File activesupport/lib/active_support/core_ext/time/calculations.rb, line 10
def ===(other)
  super || (self == Time && other.is_a?(ActiveSupport::TimeWithZone))
end
_load(marshaled_time)
# File activesupport/lib/active_support/core_ext/time/marshal.rb, line 8
def _load(marshaled_time)
  time = _load_without_utc_flag(marshaled_time)
  time.instance_eval do
    if defined?(@marshal_with_utc_coercion)
      val = remove_instance_variable("@marshal_with_utc_coercion")
    end
    val ? utc : self
  end
end
_load_without_utc_flag(marshaled_time)
_load_without_zone(marshaled_time)
current()

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

# File activesupport/lib/active_support/core_ext/time/calculations.rb, line 43
def current
  ::Time.zone ? ::Time.zone.now : ::Time.now
end
days_in_month(month, year = now.year)

Return the number of days in the given month. If no year is specified, it will use the current year.

# File activesupport/lib/active_support/core_ext/time/calculations.rb, line 16
def days_in_month(month, year = now.year)
  return 29 if month == 2 && ::Date.gregorian_leap?(year)
  COMMON_YEAR_DAYS_IN_MONTH[month]
end
find_zone(time_zone)
# File activesupport/lib/active_support/core_ext/time/zones.rb, line 65
def find_zone(time_zone)
  find_zone!(time_zone) rescue nil
end
find_zone!(time_zone)

Returns a TimeZone instance or nil, or raises an ArgumentError for invalid timezones.

# File activesupport/lib/active_support/core_ext/time/zones.rb, line 53
def find_zone!(time_zone)
  return time_zone if time_zone.nil? || time_zone.is_a?(ActiveSupport::TimeZone)
  # lookup timezone based on identifier (unless we've been passed a TZInfo::Timezone)
  unless time_zone.respond_to?(:period_for_local)
    time_zone = ActiveSupport::TimeZone[time_zone] || TZInfo::Timezone.get(time_zone)
  end
  # Return if a TimeZone instance, or wrap in a TimeZone instance if a TZInfo::Timezone
  time_zone.is_a?(ActiveSupport::TimeZone) ? time_zone : ActiveSupport::TimeZone.create(time_zone.name, nil, time_zone)
rescue TZInfo::InvalidTimezoneIdentifier
  raise ArgumentError, "Invalid Timezone: #{time_zone}"
end
local_time(*args)

Wraps class method time_with_datetime_fallback with utc_or_local set to :local.

# File activesupport/lib/active_support/core_ext/time/calculations.rb, line 38
def local_time(*args)
  time_with_datetime_fallback(:local, *args)
end
time_with_datetime_fallback(utc_or_local, year, month=1, day=1, hour=0, min=0, sec=0, usec=0)

Returns a new Time if requested year can be accommodated by Ruby’s Time class (i.e., if year is within either 1970..2038 or 1902..2038, depending on system architecture); otherwise returns a DateTime.

# File activesupport/lib/active_support/core_ext/time/calculations.rb, line 24
def time_with_datetime_fallback(utc_or_local, year, month=1, day=1, hour=0, min=0, sec=0, usec=0)
  time = ::Time.send(utc_or_local, year, month, day, hour, min, sec, usec)
  # This check is needed because Time.utc(y) returns a time object in the 2000s for 0 <= y <= 138.
  time.year == year ? time : ::DateTime.civil_from_format(utc_or_local, year, month, day, hour, min, sec)
rescue
  ::DateTime.civil_from_format(utc_or_local, year, month, day, hour, min, sec)
end
use_zone(time_zone)

Allows override of Time.zone locally inside supplied block; resets Time.zone to existing value when done.

# File activesupport/lib/active_support/core_ext/time/zones.rb, line 42
def use_zone(time_zone)
  new_zone = find_zone!(time_zone)
  begin
    old_zone, ::Time.zone = ::Time.zone, new_zone
    yield
  ensure
    ::Time.zone = old_zone
  end
end
utc_time(*args)

Wraps class method time_with_datetime_fallback with utc_or_local set to :utc.

# File activesupport/lib/active_support/core_ext/time/calculations.rb, line 33
def utc_time(*args)
  time_with_datetime_fallback(:utc, *args)
end
zone()

Returns the TimeZone for the current request, if this has been set (via ::zone=). If Time.zone has not been set for the current request, returns the TimeZone specified in config.time_zone.

# File activesupport/lib/active_support/core_ext/time/zones.rb, line 10
def zone
  Thread.current[:time_zone] || zone_default
end
zone=(time_zone)

Sets Time.zone to a TimeZone object for the current request/thread.

This method accepts any of the following:

  • A Rails TimeZone object.

  • An identifier for a Rails TimeZone object (e.g., “Eastern Time (US & Canada)”, -5.hours).

  • A TZInfo::Timezone object.

  • An identifier for a TZInfo::Timezone object (e.g., “America/New_York”).

Here’s an example of how you might set Time.zone on a per request basis and reset it when the request is done. current_user.time_zone just needs to return a string identifying the user’s preferred time zone:

class ApplicationController < ActionController::Base
  around_filter :set_time_zone

  def set_time_zone
    old_time_zone = Time.zone
    Time.zone = current_user.time_zone if logged_in?
    yield
  ensure
    Time.zone = old_time_zone
  end
end
# File activesupport/lib/active_support/core_ext/time/zones.rb, line 37
def zone=(time_zone)
  Thread.current[:time_zone] = find_zone!(time_zone)
end
Instance Public methods
-(other)
<=>(other)
Also aliased as: compare_without_coercion
_dump(*args)
# File activesupport/lib/active_support/core_ext/time/marshal.rb, line 20
def _dump(*args)
  obj = dup
  obj.instance_variable_set('@marshal_with_utc_coercion', utc?)
  obj._dump_without_utc_flag(*args)
end
_dump_without_utc_flag(*args)
_dump_without_zone(*args)
acts_like_time?()

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

# File activesupport/lib/active_support/core_ext/time/acts_like.rb, line 5
def acts_like_time?
  true
end
advance(options)

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 activesupport/lib/active_support/core_ext/time/calculations.rb, line 88
def advance(options)
  unless options[:weeks].nil?
    options[:weeks], partial_weeks = options[:weeks].divmod(1)
    options[:days] = (options[:days] || 0) + 7 * partial_weeks
  end

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

  d = to_date.advance(options)
  time_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 ? time_advanced_by_date : time_advanced_by_date.since(seconds_to_advance)
end
ago(seconds)

Returns a new Time representing the time a number of seconds ago, this is basically a wrapper around the Numeric extension

# File activesupport/lib/active_support/core_ext/time/calculations.rb, line 106
def ago(seconds)
  since(-seconds)
end
all_day()

Returns a Range representing the whole day of the current time.

# File activesupport/lib/active_support/core_ext/time/calculations.rb, line 286
def all_day
  beginning_of_day..end_of_day
end
all_month()

Returns a Range representing the whole month of the current time.

# File activesupport/lib/active_support/core_ext/time/calculations.rb, line 296
def all_month
  beginning_of_month..end_of_month
end
all_quarter()

Returns a Range representing the whole quarter of the current time.

# File activesupport/lib/active_support/core_ext/time/calculations.rb, line 301
def all_quarter
  beginning_of_quarter..end_of_quarter
end
all_week(start_day = :monday)

Returns a Range representing the whole week of the current time. Week starts on start_day (default is :monday, i.e. end of Sunday).

# File activesupport/lib/active_support/core_ext/time/calculations.rb, line 291
def all_week(start_day = :monday)
  beginning_of_week(start_day)..end_of_week(start_day)
end
all_year()

Returns a Range representing the whole year of the current time.

# File activesupport/lib/active_support/core_ext/time/calculations.rb, line 306
def all_year
  beginning_of_year..end_of_year
end
at_beginning_of_day()
at_beginning_of_hour()
at_beginning_of_month()
at_beginning_of_quarter()
at_beginning_of_week(start_day = :monday)
at_beginning_of_year()
at_end_of_month()
at_end_of_quarter()
at_end_of_week(start_day = :monday)
at_end_of_year()
at_midnight()
beginning_of_day()

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

# File activesupport/lib/active_support/core_ext/time/calculations.rb, line 208
def beginning_of_day
  #(self - seconds_since_midnight).change(:usec => 0)
  change(:hour => 0)
end
beginning_of_hour()

Returns a new Time representing the start of the hour (x:00)

Also aliased as: at_beginning_of_hour
# File activesupport/lib/active_support/core_ext/time/calculations.rb, line 222
def beginning_of_hour
  change(:min => 0)
end
beginning_of_month()

Returns a new Time representing the start of the month (1st of the month, 0:00)

Also aliased as: at_beginning_of_month
# File activesupport/lib/active_support/core_ext/time/calculations.rb, line 237
def beginning_of_month
  #self - ((self.mday-1).days + self.seconds_since_midnight)
  change(:day => 1, :hour => 0)
end
beginning_of_quarter()

Returns a new Time representing the start of the quarter (1st of january, april, july, october, 0:00)

Also aliased as: at_beginning_of_quarter
# File activesupport/lib/active_support/core_ext/time/calculations.rb, line 252
def beginning_of_quarter
  beginning_of_month.change(:month => [10, 7, 4, 1].detect { |m| m <= month })
end
beginning_of_week(start_day = :monday)

Returns a new Time representing the “start” of this week, week starts on start_day (default is :monday, i.e. Monday, 0:00).

Also aliased as: at_beginning_of_week
# File activesupport/lib/active_support/core_ext/time/calculations.rb, line 172
def beginning_of_week(start_day = :monday)
  days_to_start = days_to_week_start(start_day)
  (self - days_to_start.days).midnight
end
beginning_of_year()

Returns a new Time representing the start of the year (1st of january, 0:00)

Also aliased as: at_beginning_of_year
# File activesupport/lib/active_support/core_ext/time/calculations.rb, line 264
def beginning_of_year
  change(:month => 1, :day => 1, :hour => 0)
end
change(options)

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

# File activesupport/lib/active_support/core_ext/time/calculations.rb, line 71
def change(options)
  ::Time.send(
    utc? ? :utc_time : :local_time,
    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[:usec]  || ((options[:hour] || options[:min] || options[:sec]) ? 0 : usec)
  )
end
compare_with_coercion(other)

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

Also aliased as: <=>
# File activesupport/lib/active_support/core_ext/time/calculations.rb, line 342
def compare_with_coercion(other)
  # we're avoiding Time#to_datetime cause it's expensive
  other.is_a?(Time) ? compare_without_coercion(other.to_time) : to_datetime <=> other
end
compare_without_coercion(other)
days_to_week_start(start_day = :monday)

Returns number of days to start of this week, week starts on start_day (default is :monday).

# File activesupport/lib/active_support/core_ext/time/calculations.rb, line 164
def days_to_week_start(start_day = :monday)
  start_day_number = DAYS_INTO_WEEK[start_day]
  current_day_number = wday != 0 ? wday - 1 : 6
  days_span = current_day_number - start_day_number
  days_span >= 0 ? days_span : 7 + days_span
end
end_of_day()

Returns a new Time representing the end of the day, 23:59:59.999999 (.999999999 in ruby1.9)

# File activesupport/lib/active_support/core_ext/time/calculations.rb, line 217
def end_of_day
  change(:hour => 23, :min => 59, :sec => 59, :usec => 999999.999)
end
end_of_hour()

Returns a new Time representing the end of the hour, x:59:59.999999 (.999999999 in ruby1.9)

# File activesupport/lib/active_support/core_ext/time/calculations.rb, line 228
def end_of_hour
  change(
    :min => 59,
    :sec => 59,
    :usec => 999999.999
  )
end
end_of_month()

Returns a new Time representing the end of the month (end of the last day of the month)

Also aliased as: at_end_of_month
# File activesupport/lib/active_support/core_ext/time/calculations.rb, line 244
def end_of_month
  #self - ((self.mday-1).days + self.seconds_since_midnight)
  last_day = ::Time.days_in_month(month, year)
  change(:day => last_day, :hour => 23, :min => 59, :sec => 59, :usec => 999999.999)
end
end_of_quarter()

Returns a new Time representing the end of the quarter (end of the last day of march, june, september, december)

Also aliased as: at_end_of_quarter
# File activesupport/lib/active_support/core_ext/time/calculations.rb, line 258
def end_of_quarter
  beginning_of_month.change(:month => [3, 6, 9, 12].detect { |m| m >= month }).end_of_month
end
end_of_week(start_day = :monday)

Returns a new Time representing the end of this week, week starts on start_day (default is :monday, i.e. end of Sunday).

Also aliased as: at_end_of_week
# File activesupport/lib/active_support/core_ext/time/calculations.rb, line 185
def end_of_week(start_day = :monday)
  days_to_end =  6 - days_to_week_start(start_day)
  (self + days_to_end.days).end_of_day
end
end_of_year()

Returns a new Time representing the end of the year (end of the 31st of december)

Also aliased as: at_end_of_year
# File activesupport/lib/active_support/core_ext/time/calculations.rb, line 270
def end_of_year
  change(:month => 12, :day => 31, :hour => 23, :min => 59, :sec => 59, :usec => 999999.999)
end
eql?(other)
Also aliased as: eql_without_coercion
eql_with_coercion(other)

Layers additional behavior on #eql? so that ActiveSupport::TimeWithZone instances can be eql? to an equivalent Time

Also aliased as: eql?
# File activesupport/lib/active_support/core_ext/time/calculations.rb, line 351
def eql_with_coercion(other)
  # if other is an ActiveSupport::TimeWithZone, coerce a Time instance from it so we can do eql? comparison
  other = other.comparable_time if other.respond_to?(:comparable_time)
  eql_without_coercion(other)
end
eql_without_coercion(other)
formatted_offset(colon = true, alternate_utc_string = nil)

Returns the UTC offset as an +HH:MM formatted string.

Time.local(2000).formatted_offset         # => "-06:00"
Time.local(2000).formatted_offset(false)  # => "-0600"
# File activesupport/lib/active_support/core_ext/time/conversions.rb, line 54
def formatted_offset(colon = true, alternate_utc_string = nil)
  utc? && alternate_utc_string || ActiveSupport::TimeZone.seconds_to_utc_offset(utc_offset, colon)
end
future?()

Tells whether the Time object’s time lies in the future

# File activesupport/lib/active_support/core_ext/time/calculations.rb, line 59
def future?
  self > ::Time.current
end
in(seconds)
in_time_zone(zone = ::Time.zone)

Returns the simultaneous time in Time.zone.

Time.zone = 'Hawaii'         # => 'Hawaii'
Time.utc(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.

Time.utc(2000).in_time_zone('Alaska')  # => Fri, 31 Dec 1999 15:00:00 AKST -09:00
# File activesupport/lib/active_support/core_ext/time/zones.rb, line 82
def in_time_zone(zone = ::Time.zone)
  return self unless zone

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

Time#- can also be used to determine the number of seconds between two Time instances. We’re layering on additional behavior so that ActiveSupport::TimeWithZone instances are coerced into values that Time#- will recognize

Also aliased as: -
# File activesupport/lib/active_support/core_ext/time/calculations.rb, line 333
def minus_with_coercion(other)
  other = other.comparable_time if other.respond_to?(:comparable_time)
  other.is_a?(DateTime) ? to_f - other.to_f : minus_without_coercion(other)
end
minus_without_coercion(other)
minus_without_duration(other)
monday()

Returns a new Date/DateTime representing the start of this week. Week is assumed to start on a Monday. DateTime objects have their time set to 0:00.

# File activesupport/lib/active_support/core_ext/time/calculations.rb, line 180
def monday
  beginning_of_week
end
months_ago(months)

Returns a new Time representing the time a number of specified months ago

# File activesupport/lib/active_support/core_ext/time/calculations.rb, line 124
def months_ago(months)
  advance(:months => -months)
end
months_since(months)

Returns a new Time representing the time a number of specified months in the future

# File activesupport/lib/active_support/core_ext/time/calculations.rb, line 129
def months_since(months)
  advance(:months => months)
end
next_month()

Short-hand for #months_since(1)

# File activesupport/lib/active_support/core_ext/time/calculations.rb, line 159
def next_month
  months_since(1)
end
next_week(day = :monday)

Returns a new Time representing the start of the given day in next week (default is :monday).

# File activesupport/lib/active_support/core_ext/time/calculations.rb, line 203
def next_week(day = :monday)
  since(1.week).beginning_of_week.since(DAYS_INTO_WEEK[day].day).change(:hour => 0)
end
next_year()

Short-hand for #years_since(1)

# File activesupport/lib/active_support/core_ext/time/calculations.rb, line 149
def next_year
  years_since(1)
end
past?()

Tells whether the Time object’s time lies in the past

# File activesupport/lib/active_support/core_ext/time/calculations.rb, line 49
def past?
  self < ::Time.current
end
prev_month()

Short-hand for #months_ago(1)

# File activesupport/lib/active_support/core_ext/time/calculations.rb, line 154
def prev_month
  months_ago(1)
end
prev_week(day = :monday)

Returns a new Time representing the start of the given day in the previous week (default is :monday).

# File activesupport/lib/active_support/core_ext/time/calculations.rb, line 198
def prev_week(day = :monday)
  ago(1.week).beginning_of_week.since(DAYS_INTO_WEEK[day].day).change(:hour => 0)
end
prev_year()

Short-hand for #years_ago(1)

# File activesupport/lib/active_support/core_ext/time/calculations.rb, line 144
def prev_year
  years_ago(1)
end
seconds_since_midnight()

Seconds since midnight: Time.now.#seconds_since_midnight

# File activesupport/lib/active_support/core_ext/time/calculations.rb, line 64
def seconds_since_midnight
  to_i - change(:hour => 0).to_i + (usec / 1.0e+6)
end
since(seconds)

Returns a new Time representing the time a number of seconds since the instance time

Also aliased as: in
# File activesupport/lib/active_support/core_ext/time/calculations.rb, line 111
def since(seconds)
  self + seconds
rescue
  to_datetime.since(seconds)
end
sunday()

Returns a new Date/DateTime representing the end of this week. Week is assumed to start on a Monday. DateTime objects have their time set to 23:59:59.

# File activesupport/lib/active_support/core_ext/time/calculations.rb, line 193
def sunday
  end_of_week
end
to_date()

Converts a Time object to a Date, dropping hour, minute, and second precision.

my_time = Time.now  # => Mon Nov 12 22:59:51 -0500 2007
my_time.to_date     # => Mon, 12 Nov 2007

your_time = Time.parse("1/13/2009 1:13:03 P.M.")  # => Tue Jan 13 13:13:03 -0500 2009
your_time.to_date                                 # => Tue, 13 Jan 2009
# File activesupport/lib/active_support/core_ext/time/conversions.rb, line 65
def to_date
  ::Date.new(year, month, day)
end
to_datetime()

Converts a Time instance to a Ruby DateTime instance, preserving UTC offset.

my_time = Time.now    # => Mon Nov 12 23:04:21 -0500 2007
my_time.to_datetime   # => Mon, 12 Nov 2007 23:04:21 -0500

your_time = Time.parse("1/13/2009 1:13:03 P.M.")  # => Tue Jan 13 13:13:03 -0500 2009
your_time.to_datetime                             # => Tue, 13 Jan 2009 13:13:03 -0500
# File activesupport/lib/active_support/core_ext/time/conversions.rb, line 82
def to_datetime
  ::DateTime.civil(year, month, day, hour, min, sec, Rational(utc_offset, 86400))
end
to_default_s(format = :default)
to_formatted_s(format = :default)

Converts to a formatted string. See DATE_FORMATS for builtin formats.

This method is aliased to to_s.

time = Time.now                     # => Thu Jan 18 06:10:17 CST 2007

time.to_formatted_s(:time)          # => "06:10"
time.to_s(:time)                    # => "06:10"

time.to_formatted_s(:db)            # => "2007-01-18 06:10:17"
time.to_formatted_s(:number)        # => "20070118061017"
time.to_formatted_s(:short)         # => "18 Jan 06:10"
time.to_formatted_s(:long)          # => "January 18, 2007 06:10"
time.to_formatted_s(:long_ordinal)  # => "January 18th, 2007 06:10"
time.to_formatted_s(:rfc822)        # => "Thu, 18 Jan 2007 06:10:17 -0600"

Adding your own time formats to to_formatted_s

You can add your own formats 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 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}") }
Also aliased as: to_s
# File activesupport/lib/active_support/core_ext/time/conversions.rb, line 40
def to_formatted_s(format = :default)
  if formatter = DATE_FORMATS[format]
    formatter.respond_to?(:call) ? formatter.call(self).to_s : strftime(formatter)
  else
    to_default_s
  end
end
to_s(format = :default)
Also aliased as: to_default_s
to_time()

A method to keep Time, Date and DateTime instances interchangeable on conversions. In this case, it simply returns self.

# File activesupport/lib/active_support/core_ext/time/conversions.rb, line 71
def to_time
  self
end
today?()

Tells whether the Time object’s time is today

# File activesupport/lib/active_support/core_ext/time/calculations.rb, line 54
def today?
  to_date == ::Date.current
end
tomorrow()

Convenience method which returns a new Time representing the time 1 day since the instance time

# File activesupport/lib/active_support/core_ext/time/calculations.rb, line 281
def tomorrow
  advance(:days => 1)
end
weeks_ago(weeks)

Returns a new Time representing the time a number of specified weeks ago.

# File activesupport/lib/active_support/core_ext/time/calculations.rb, line 119
def weeks_ago(weeks)
  advance(:weeks => -weeks)
end
years_ago(years)

Returns a new Time representing the time a number of specified years ago

# File activesupport/lib/active_support/core_ext/time/calculations.rb, line 134
def years_ago(years)
  advance(:years => -years)
end
years_since(years)

Returns a new Time representing the time a number of specified years in the future

# File activesupport/lib/active_support/core_ext/time/calculations.rb, line 139
def years_since(years)
  advance(:years => years)
end
yesterday()

Convenience method which returns a new Time representing the time 1 day ago

# File activesupport/lib/active_support/core_ext/time/calculations.rb, line 276
def yesterday
  advance(:days => -1)
end