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:
-
date-time defined by RFC 2822
-
HTTP-date defined by RFC 2616
-
various formats handled by Date._parse
-
custom formats handled by Date._strptime
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
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; }
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); }
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
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
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); }
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); }
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); }
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
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,