class Time

time.rb

When 'time' is required, Time is extended with additional methods for parsing and converting Times.

Features

This library extends the Time class with the following conversions between date strings and Time objects:

Examples

All examples assume you have loaded Time with:

require 'time'

All of these examples were done using the EST timezone which is GMT-5.

Converting to a String

t = Time.now
t.iso8601  # => "2011-10-05T22:26:12-04:00"
t.rfc2822  # => "Wed, 05 Oct 2011 22:26:12 -0400"
t.httpdate # => "Thu, 06 Oct 2011 02:26:12 GMT"

::parse

parse takes a string representation of a Time and attempts to parse it using a heuristic.

Time.parse("2010-10-31") #=> 2010-10-31 00:00:00 -0500

Any missing pieces of the date are inferred based on the current date.

# assuming the current date is "2011-10-31"
Time.parse("12:00") #=> 2011-10-31 12:00:00 -0500

We can change the date used to infer our missing elements by passing a second object that responds to mon, day and year, such as Date, Time or DateTime. We can also use our own object.

class MyDate
  attr_reader :mon, :day, :year

  def initialize(mon, day, year)
    @mon, @day, @year = mon, day, year
  end
end

d  = Date.parse("2010-10-28")
t  = Time.parse("2010-10-29")
dt = DateTime.parse("2010-10-30")
md = MyDate.new(10,31,2010)

Time.parse("12:00", d)  #=> 2010-10-28 12:00:00 -0500
Time.parse("12:00", t)  #=> 2010-10-29 12:00:00 -0500
Time.parse("12:00", dt) #=> 2010-10-30 12:00:00 -0500
Time.parse("12:00", md) #=> 2010-10-31 12:00:00 -0500

parse also accepts an optional block. You can use this block to specify how to handle the year component of the date. This is specifically designed for handling two digit years. For example, if you wanted to treat all two digit years prior to 70 as the year 2000+ you could write this:

Time.parse("01-10-31") {|year| year + (year < 70 ? 2000 : 1900)}
#=> 2001-10-31 00:00:00 -0500
Time.parse("70-10-31") {|year| year + (year < 70 ? 2000 : 1900)}
#=> 1970-10-31 00:00:00 -0500

::strptime

strptime works similar to parse except that instead of using a heuristic to detect the format of the input string, you provide a second argument that describes the format of the string. For example:

Time.strptime("2000-10-31", "%Y-%m-%d") #=> 2000-10-31 00:00:00 -0500

Time is an abstraction of dates and times. Time is stored internally as the number of seconds with fraction since the Epoch, January 1, 1970 00:00 UTC. Also see the library module Date. The Time class treats GMT (Greenwich Mean Time) and UTC (Coordinated Universal Time) as equivalent. GMT is the older way of referring to these baseline times but persists in the names of calls on POSIX systems.

All times may have fraction. Be aware of this fact when comparing times with each other – times that are apparently equal when displayed may be different when compared.

Since Ruby 1.9.2, Time implementation uses a signed 63 bit integer, Bignum or Rational. The integer is a number of nanoseconds since the Epoch which can represent 1823-11-12 to 2116-02-20. When Bignum or Rational is used (before 1823, after 2116, under nanosecond), Time works slower as when integer is used.

Examples

All of these examples were done using the EST timezone which is GMT-5.

Creating a new Time instance

You can create a new instance of Time with ::new. This will use the current system time. ::now is an alias for this. You can also pass parts of the time to ::new such as year, month, minute, etc. When you want to construct a time this way you must pass at least a year. If you pass the year with nothing else time will default to January 1 of that year at 00:00:00 with the current system timezone. Here are some examples:

Time.new(2002)         #=> 2002-01-01 00:00:00 -0500
Time.new(2002, 10)     #=> 2002-10-01 00:00:00 -0500
Time.new(2002, 10, 31) #=> 2002-10-31 00:00:00 -0500
Time.new(2002, 10, 31, 2, 2, 2, "+02:00") #=> 2002-10-31 02:02:02 +0200

You can also use gm, local and utc to infer GMT, local and UTC timezones instead of using the current system setting.

You can also create a new time using ::at which takes the number of seconds (or fraction of seconds) since the Unix Epoch.

Time.at(628232400) #=> 1989-11-28 00:00:00 -0500

Working with an instance of Time

Once you have an instance of Time there is a multitude of things you can do with it. Below are some examples. For all of the following examples, we will work on the assumption that you have done the following:

t = Time.new(1993, 02, 24, 12, 0, 0, "+09:00")

Was that a monday?

t.monday? #=> false

What year was that again?

t.year #=> 1993

Was it daylight savings at the time?

t.dst? #=> false

What's the day a year later?

t + (60*60*24*365) #=> 1994-02-24 12:00:00 +0900

How many seconds was that since the Unix Epoch?

t.to_i #=> 730522800

You can also do standard functions like compare two times.

t1 = Time.new(2010)
t2 = Time.new(2011)

t1 == t2 #=> false
t1 == t1 #=> true
t1 <  t2 #=> true
t1 >  t2 #=> false

Time.new(2010,10,31).between?(t1, t2) #=> true

Public Class Methods

at(time) → time click to toggle source
at(seconds_with_frac) → time
at(seconds, microseconds_with_frac) → time
at(seconds, milliseconds, :millisecond) → time
at(seconds, microseconds, :usec) → time
at(seconds, microseconds, :microsecond) → time
at(seconds, nanoseconds, :nsec) → time
at(seconds, nanoseconds, :nanosecond) → time

Creates a new Time object with the value given by time, the given number of seconds_with_frac, or seconds and microseconds_with_frac since the Epoch. seconds_with_frac and microseconds_with_frac can be an Integer, Float, Rational, or other Numeric. non-portable feature allows the offset to be negative on some systems.

If a numeric argument is given, the result is in local time.

Time.at(0)                                #=> 1969-12-31 18:00:00 -0600
Time.at(Time.at(0))                       #=> 1969-12-31 18:00:00 -0600
Time.at(946702800)                        #=> 1999-12-31 23:00:00 -0600
Time.at(-284061600)                       #=> 1960-12-31 00:00:00 -0600
Time.at(946684800.2).usec                 #=> 200000
Time.at(946684800, 123456.789).nsec       #=> 123456789
Time.at(946684800, 123456789, :nsec).nsec  #=> 123456789
static VALUE
time_s_at(int argc, VALUE *argv, VALUE klass)
{
    VALUE time, t, unit = Qundef;
    wideval_t timew;

    if (rb_scan_args(argc, argv, "12", &time, &t, &unit) >= 2) {
        int scale = argc == 3 ? get_scale(unit) : 1000000;
        time = num_exact(time);
        t = num_exact(t);
        timew = wadd(rb_time_magnify(v2w(time)), wmulquoll(v2w(t), TIME_SCALE, scale));
        t = time_new_timew(klass, timew);
    }
    else if (IsTimeval(time)) {
        struct time_object *tobj, *tobj2;
        GetTimeval(time, tobj);
        t = time_new_timew(klass, tobj->timew);
        GetTimeval(t, tobj2);
        TIME_COPY_GMT(tobj2, tobj);
    }
    else {
        timew = rb_time_magnify(v2w(num_exact(time)));
        t = time_new_timew(klass, timew);
    }

    return t;
}
gm(year) → time click to toggle source
gm(year, month) → time
gm(year, month, day) → time
gm(year, month, day, hour) → time
gm(year, month, day, hour, min) → time
gm(year, month, day, hour, min, sec_with_frac) → time
gm(year, month, day, hour, min, sec, usec_with_frac) → time
gm(sec, min, hour, day, month, year, dummy, dummy, dummy, dummy) → time

Creates a Time object based on given values, interpreted as UTC (GMT). The year must be specified. Other values default to the minimum value for that field (and may be nil or omitted). Months may be specified by numbers from 1 to 12, or by the three-letter English month names. Hours are specified on a 24-hour clock (0..23). Raises an ArgumentError if any values are out of range. Will also accept ten arguments in the order output by #to_a.

sec_with_frac and usec_with_frac can have a fractional part.

Time.utc(2000,"jan",1,20,15,1)  #=> 2000-01-01 20:15:01 UTC
Time.gm(2000,"jan",1,20,15,1)   #=> 2000-01-01 20:15:01 UTC
static VALUE
time_s_mkutc(int argc, VALUE *argv, VALUE klass)
{
    return time_utc_or_local(argc, argv, TRUE, klass);
}
httpdate(date) click to toggle source

Parses date as an HTTP-date defined by RFC 2616 and converts it to a Time object.

ArgumentError is raised if date is not compliant with RFC 2616 or if the Time class cannot represent specified date.

See httpdate for more information on this format.

You must require 'time' to use this method.

# File lib/time.rb, line 522
def httpdate(date)
  if /\A\s*
      (?:Mon|Tue|Wed|Thu|Fri|Sat|Sun),\x20
      (\d{2})\x20
      (Jan|Feb|Mar|Apr|May|Jun|Jul|Aug|Sep|Oct|Nov|Dec)\x20
      (\d{4})\x20
      (\d{2}):(\d{2}):(\d{2})\x20
      GMT
      \s*\z/ix =~ date
    self.rfc2822(date).utc
  elsif /\A\s*
         (?:Monday|Tuesday|Wednesday|Thursday|Friday|Saturday|Sunday),\x20
         (\d\d)-(Jan|Feb|Mar|Apr|May|Jun|Jul|Aug|Sep|Oct|Nov|Dec)-(\d\d)\x20
         (\d\d):(\d\d):(\d\d)\x20
         GMT
         \s*\z/ix =~ date
    year = $3.to_i
    if year < 50
      year += 2000
    else
      year += 1900
    end
    self.utc(year, $2, $1.to_i, $4.to_i, $5.to_i, $6.to_i)
  elsif /\A\s*
         (?:Mon|Tue|Wed|Thu|Fri|Sat|Sun)\x20
         (Jan|Feb|Mar|Apr|May|Jun|Jul|Aug|Sep|Oct|Nov|Dec)\x20
         (\d\d|\x20\d)\x20
         (\d\d):(\d\d):(\d\d)\x20
         (\d{4})
         \s*\z/ix =~ date
    self.utc($6.to_i, MonthValue[$1.upcase], $2.to_i,
             $3.to_i, $4.to_i, $5.to_i)
  else
    raise ArgumentError.new("not RFC 2616 compliant date: #{date.inspect}")
  end
end
iso8601(date)
Alias for: xmlschema
json_create(object) click to toggle source

Deserializes JSON string by converting time since epoch to Time

# File ext/json/lib/json/add/time.rb, line 9
def self.json_create(object)
  if usec = object.delete('u') # used to be tv_usec -> tv_nsec
    object['n'] = usec * 1000
  end
  if method_defined?(:tv_nsec)
    at(object['s'], Rational(object['n'], 1000))
  else
    at(object['s'], object['n'] / 1000)
  end
end
local(year) → time click to toggle source
local(year, month) → time
local(year, month, day) → time
local(year, month, day, hour) → time
local(year, month, day, hour, min) → time
local(year, month, day, hour, min, sec_with_frac) → time
local(year, month, day, hour, min, sec, usec_with_frac) → time
local(sec, min, hour, day, month, year, dummy, dummy, isdst, dummy) → time

Same as ::gm, but interprets the values in the local time zone.

Time.local(2000,"jan",1,20,15,1)   #=> 2000-01-01 20:15:01 -0600
static VALUE
time_s_mktime(int argc, VALUE *argv, VALUE klass)
{
    return time_utc_or_local(argc, argv, FALSE, klass);
}
mktime(year) → time click to toggle source
mktime(year, month) → time
mktime(year, month, day) → time
mktime(year, month, day, hour) → time
mktime(year, month, day, hour, min) → time
mktime(year, month, day, hour, min, sec_with_frac) → time
mktime(year, month, day, hour, min, sec, usec_with_frac) → time
mktime(sec, min, hour, day, month, year, dummy, dummy, isdst, dummy) → time

Same as ::gm, but interprets the values in the local time zone.

Time.local(2000,"jan",1,20,15,1)   #=> 2000-01-01 20:15:01 -0600
static VALUE
time_s_mktime(int argc, VALUE *argv, VALUE klass)
{
    return time_utc_or_local(argc, argv, FALSE, klass);
}
new → time click to toggle source
new(year, month=nil, day=nil, hour=nil, min=nil, sec=nil, utc_offset=nil) → time

Returns a Time object.

It is initialized to the current system time if no argument is given.

Note: The new object will use the resolution available on your system clock, and may include fractional seconds.

If one or more arguments specified, the time is initialized to the specified time.

sec may have fraction if it is a rational.

utc_offset is the offset from UTC. It can be a string such as “+09:00” or a number of seconds such as 32400.

a = Time.new      #=> 2007-11-19 07:50:02 -0600
b = Time.new      #=> 2007-11-19 07:50:02 -0600
a == b            #=> false
"%.6f" % a.to_f   #=> "1195480202.282373"
"%.6f" % b.to_f   #=> "1195480202.283415"

Time.new(2008,6,21, 13,30,0, "+09:00") #=> 2008-06-21 13:30:00 +0900

# A trip for RubyConf 2007
t1 = Time.new(2007,11,1,15,25,0, "+09:00") # JST (Narita)
t2 = Time.new(2007,11,1,12, 5,0, "-05:00") # CDT (Minneapolis)
t3 = Time.new(2007,11,1,13,25,0, "-05:00") # CDT (Minneapolis)
t4 = Time.new(2007,11,1,16,53,0, "-04:00") # EDT (Charlotte)
t5 = Time.new(2007,11,5, 9,24,0, "-05:00") # EST (Charlotte)
t6 = Time.new(2007,11,5,11,21,0, "-05:00") # EST (Detroit)
t7 = Time.new(2007,11,5,13,45,0, "-05:00") # EST (Detroit)
t8 = Time.new(2007,11,6,17,10,0, "+09:00") # JST (Narita)
p((t2-t1)/3600.0)                          #=> 10.666666666666666
p((t4-t3)/3600.0)                          #=> 2.466666666666667
p((t6-t5)/3600.0)                          #=> 1.95
p((t8-t7)/3600.0)                          #=> 13.416666666666666
static VALUE
time_init(int argc, VALUE *argv, VALUE time)
{
    if (argc == 0)
        return time_init_0(time);
    else
        return time_init_1(argc, argv, time);
}
now → time click to toggle source

Creates a new Time object for the current time. This is same as ::new without arguments.

Time.now            #=> 2009-06-24 12:39:54 +0900
static VALUE
time_s_now(VALUE klass)
{
    return rb_class_new_instance(0, NULL, klass);
}
parse(date, now=self.now) { |year| ... } click to toggle source

Parses date using Date._parse and converts it to a Time object.

If a block is given, the year described in date is converted by the block. For example:

Time.parse(...) {|y| 0 <= y && y < 100 ? (y >= 69 ? y + 1900 : y + 2000) : y}

If the upper components of the given time are broken or missing, they are supplied with those of now. For the lower components, the minimum values (1 or 0) are assumed if broken or missing. For example:

# Suppose it is "Thu Nov 29 14:33:20 2001" now and
# your time zone is EST which is GMT-5.
now = Time.parse("Thu Nov 29 14:33:20 2001")
Time.parse("16:30", now)     #=> 2001-11-29 16:30:00 -0500
Time.parse("7/23", now)      #=> 2001-07-23 00:00:00 -0500
Time.parse("Aug 31", now)    #=> 2001-08-31 00:00:00 -0500
Time.parse("Aug 2000", now)  #=> 2000-08-01 00:00:00 -0500

Since there are numerous conflicts among locally defined time zone abbreviations all over the world, this method is not intended to understand all of them. For example, the abbreviation “CST” is used variously as:

-06:00 in America/Chicago,
-05:00 in America/Havana,
+08:00 in Asia/Harbin,
+09:30 in Australia/Darwin,
+10:30 in Australia/Adelaide,
etc.

Based on this fact, this method only understands the time zone abbreviations described in RFC 822 and the system time zone, in the order named. (i.e. a definition in RFC 822 overrides the system time zone definition.) The system time zone is taken from Time.local(year, 1, 1).zone and Time.local(year, 7, 1).zone. If the extracted time zone abbreviation does not match any of them, it is ignored and the given time is regarded as a local time.

ArgumentError is raised if Date._parse cannot extract information from date or if the Time class cannot represent specified date.

This method can be used as a fail-safe for other parsing methods as:

Time.rfc2822(date) rescue Time.parse(date)
Time.httpdate(date) rescue Time.parse(date)
Time.xmlschema(date) rescue Time.parse(date)

A failure of ::parse should be checked, though.

You must require 'time' to use this method.

# File lib/time.rb, line 364
def parse(date, now=self.now)
  comp = !block_given?
  d = Date._parse(date, comp)
  year = d[:year]
  year = yield(year) if year && !comp
  make_time(date, year, d[:mon], d[:mday], d[:hour], d[:min], d[:sec], d[:sec_fraction], d[:zone], now)
end
rfc2822(date) click to toggle source

Parses date as date-time defined by RFC 2822 and converts it to a Time object. The format is identical to the date format defined by RFC 822 and updated by RFC 1123.

ArgumentError is raised if date is not compliant with RFC 2822 or if the Time class cannot represent specified date.

See rfc2822 for more information on this format.

You must require 'time' to use this method.

# File lib/time.rb, line 469
def rfc2822(date)
  if /\A\s*
      (?:(?:Mon|Tue|Wed|Thu|Fri|Sat|Sun)\s*,\s*)?
      (\d{1,2})\s+
      (Jan|Feb|Mar|Apr|May|Jun|Jul|Aug|Sep|Oct|Nov|Dec)\s+
      (\d{2,})\s+
      (\d{2})\s*
      :\s*(\d{2})\s*
      (?::\s*(\d{2}))?\s+
      ([+-]\d{4}|
       UT|GMT|EST|EDT|CST|CDT|MST|MDT|PST|PDT|[A-IK-Z])/ix =~ date
    # Since RFC 2822 permit comments, the regexp has no right anchor.
    day = $1.to_i
    mon = MonthValue[$2.upcase]
    year = $3.to_i
    short_year_p = $3.length <= 3
    hour = $4.to_i
    min = $5.to_i
    sec = $6 ? $6.to_i : 0
    zone = $7

    if short_year_p
      # following year completion is compliant with RFC 2822.
      year = if year < 50
               2000 + year
             else
               1900 + year
             end
    end

    off = zone_offset(zone)
    year, mon, day, hour, min, sec =
      apply_offset(year, mon, day, hour,