Class: Time (Ruby 2.7.2)
source link: https://ruby-doc.org/core-2.7.2/Time.html
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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
You can pass a UTC offset:
Time.new(2002, 10, 31, 2, 2, 2, "+02:00") #=> 2002-10-31 02:02:02 +0200
Or a timezone object:
tz = timezone("Europe/Athens") # Eastern European Time, UTC+2
Time.new(2002, 10, 31, 2, 2, 2, tz) #=> 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
Timezone argument¶ ↑
A timezone argument must have local_to_utc and
utc_to_local methods, and may have name,
abbr, and dst? methods.
The local_to_utc method should convert a Time-like object from
the timezone to UTC, and utc_to_local is the opposite. The
result also should be a Time or Time-like object
(not necessary to be the same class). The zone of the result is just ignored.
Time-like argument to these methods is similar to a Time object in UTC without sub-second; it has
attribute readers for the parts, e.g. year, month, and so on, and epoch time
readers, to_i. The sub-second
attributes are fixed as 0, and utc_offset, zone, isdst, and their aliases are same as a
Time object in UTC. Also to_time, #+, and #-
methods are defined.
The name method is used for marshaling. If this method is not
defined on a timezone object, Time objects using
that timezone object can not be dumped by Marshal.
The abbr method is used by ‘%Z’ in strftime.
The dst? method is called with a Time value and
should return whether the Time value is in daylight savings
time in the zone.
Auto conversion to Timezone¶ ↑
At loading marshaled data, a timezone name will be converted to a timezone
object by find_timezone class method, if the method is
defined.
Similarly, that class method will be called when a timezone argument does not have the necessary methods mentioned above.
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 in argument is given, the result is in that timezone or UTC
offset, or 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
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
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
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
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 are specified, the time is initialized to the specified time.
sec may have fraction if it is a rational.
tz specifies the timezone. It can be an offset from UTC, given
either as a string such as "+09:00" or a single letter "A".."Z" excluding
"J" (so-called military time zone), or as a number of seconds such as
32400. Or it can be a timezone object, see Timezone argument for
details.
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) (t2-t1)/3600.0 #=> 10.666666666666666 (t4-t3)/3600.0 #=> 2.466666666666667 (t6-t5)/3600.0 #=> 1.95 (t8-t7)/3600.0 #=> 13.416666666666666
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
Public Instance Methods
Addition — Adds some number of seconds (possibly fractional) to time and returns that value as a new Time object.
t = Time.now #=> 2007-11-19 08:22:21 -0600 t + (60 * 60 * 24) #=> 2007-11-20 08:22:21 -0600
Difference — Returns a difference in seconds as a Float between time and
other_time, or subtracts the given number of seconds in
numeric from time.
t = Time.now #=> 2007-11-19 08:23:10 -0600 t2 = t + 2592000 #=> 2007-12-19 08:23:10 -0600 t2 - t #=> 2592000.0 t2 - 2592000 #=> 2007-11-19 08:23:10 -0600
Comparison—Compares time with other_time.
-1, 0, +1 or nil depending on whether time is less than,
equal to, or greater than other_time.
nil is returned if the two values are incomparable.
t = Time.now #=> 2007-11-19 08:12:12 -0600 t2 = t + 2592000 #=> 2007-12-19 08:12:12 -0600 t <=> t2 #=> -1 t2 <=> t #=> 1 t = Time.now #=> 2007-11-19 08:13:38 -0600 t2 = t + 0.1 #=> 2007-11-19 08:13:38 -0600 t.nsec #=> 98222999 t2.nsec #=> 198222999 t <=> t2 #=> -1 t2 <=> t #=> 1 t <=> t #=> 0
Returns a canonical string representation of time.
Time.now.asctime #=> "Wed Apr 9 08:56:03 2003" Time.now.ctime #=> "Wed Apr 9 08:56:03 2003"
Ceils sub seconds to a given precision in decimal digits (0 digits by
default). It returns a new Time object.
ndigits should be zero or a positive integer.
require 'time' t = Time.utc(2010,3,30, 5,43,25.0123456789r) t.iso8601(10) #=> "2010-03-30T05:43:25.0123456789Z" t.ceil.iso8601(10) #=> "2010-03-30T05:43:26.0000000000Z" t.ceil(0).iso8601(10) #=> "2010-03-30T05:43:26.0000000000Z" t.ceil(1).iso8601(10) #=> "2010-03-30T05:43:25.1000000000Z" t.ceil(2).iso8601(10) #=> "2010-03-30T05:43:25.0200000000Z" t.ceil(3).iso8601(10) #=> "2010-03-30T05:43:25.0130000000Z" t.ceil(4).iso8601(10) #=> "2010-03-30T05:43:25.0124000000Z" t = Time.utc(1999,12,31, 23,59,59) (t + 0.4).ceil.iso8601(3) #=> "2000-01-01T00:00:00.000Z" (t + 0.9).ceil.iso8601(3) #=> "2000-01-01T00:00:00.000Z" (t + 1.4).ceil.iso8601(3) #=> "2000-01-01T00:00:01.000Z" (t + 1.9).ceil.iso8601(3) #=> "2000-01-01T00:00:01.000Z" t = Time.utc(1999,12,31, 23,59,59) (t + 0.123456789).ceil(4).iso8601(6) #=> "1999-12-31T23:59:59.123500Z"
Returns a canonical string representation of time.
Time.now.asctime #=> "Wed Apr 9 08:56:03 2003" Time.now.ctime #=> "Wed Apr 9 08:56:03 2003"
Returns the day of the month (1..n) for time.
t = Time.now #=> 2007-11-19 08:27:03 -0600 t.day #=> 19 t.mday #=> 19
Returns true if time occurs during Daylight Saving Time in its time zone.
# CST6CDT: Time.local(2000, 1, 1).zone #=> "CST" Time.local(2000, 1, 1).isdst #=> false Time.local(2000, 1, 1).dst? #=> false Time.local(2000, 7, 1).zone #=> "CDT" Time.local(2000, 7, 1).isdst #=> true Time.local(2000, 7, 1).dst? #=> true # Asia/Tokyo: Time.local(2000, 1, 1).zone #=> "JST" Time.local(2000, 1, 1).isdst #=> false Time.local(2000, 1, 1).dst? #=> false Time.local(2000, 7, 1).zone #=> "JST" Time.local(2000, 7, 1).isdst #=> false Time.local(2000, 7, 1).dst? #=> false
Returns true if time and other_time are
both Time objects with the same seconds and
fractional seconds.
Floors sub seconds to a given precision in decimal digits (0 digits by
default). It returns a new Time object.
ndigits should be zero or a positive integer.
require 'time' t = Time.utc(2010,3,30, 5,43,25.123456789r) t.iso8601(10) #=> "2010-03-30T05:43:25.1234567890Z" t.floor.iso8601(10) #=> "2010-03-30T05:43:25.0000000000Z" t.floor(0).iso8601(10) #=> "2010-03-30T05:43:25.0000000000Z" t.floor(1).iso8601(10) #=> "2010-03-30T05:43:25.1000000000Z" t.floor(2).iso8601(10) #=> "2010-03-30T05:43:25.1200000000Z" t.floor(3).iso8601(10) #=> "2010-03-30T05:43:25.1230000000Z" t.floor(4).iso8601(10) #=> "2010-03-30T05:43:25.1234000000Z" t = Time.utc(1999,12,31, 23,59,59) (t + 0.4).floor.iso8601(3) #=> "1999-12-31T23:59:59.000Z" (t + 0.9).floor.iso8601(3) #=> "1999-12-31T23:59:59.000Z" (t + 1.4).floor.iso8601(3) #=> "2000-01-01T00:00:00.000Z" (t + 1.9).floor.iso8601(3) #=> "2000-01-01T00:00:00.000Z" t = Time.utc(1999,12,31, 23,59,59) (t + 0.123456789).floor(4).iso8601(6) #=> "1999-12-31T23:59:59.123400Z"
Returns true if time represents Friday.
t = Time.local(1987, 12, 18) #=> 1987-12-18 00:00:00 -0600 t.friday? #=> true
Returns a new Time object representing time in UTC.
t = Time.local(2000,1,1,20,15,1) #=> 2000-01-01 20:15:01 -0600 t.gmt? #=> false y = t.getgm #=> 2000-01-02 02:15:01 UTC y.gmt? #=> true t == y #=> true
Returns a new Time object representing time in local time (using the local time zone in effect for this process).
If utc_offset is given, it is used instead of the local time.
utc_offset can be given as a human-readable string (eg.
"+09:00") or as a number of seconds (eg.
32400).
t = Time.utc(2000,1,1,20,15,1) #=> 2000-01-01 20:15:01 UTC
t.utc? #=> true
l = t.getlocal #=> 2000-01-01 14:15:01 -0600
l.utc? #=> false
t == l #=> true
j = t.getlocal("+09:00") #=> 2000-01-02 05:15:01 +0900
j.utc? #=> false
t == j #=> true
k = t.getlocal(9*60*60) #=> 2000-01-02 05:15:01 +0900
k.utc? #=> false
t == k #=> true
Returns a new Time object representing time in UTC.
t = Time.local(2000,1,1,20,15,1) #=> 2000-01-01 20:15:01 -0600 t.gmt? #=> false y = t.getgm #=> 2000-01-02 02:15:01 UTC y.gmt? #=> true t == y #=> true
Returns true if time represents a time in UTC (GMT).
t = Time.now #=> 2007-11-19 08:15:23 -0600 t.utc? #=> false t = Time.gm(2000,"jan",1,20,15,1) #=> 2000-01-01 20:15:01 UTC t.utc? #=> true t = Time.now #=> 2007-11-19 08:16:03 -0600 t.gmt? #=> false t = Time.gm(2000,1,1,20,15,1) #=> 2000-01-01 20:15:01 UTC t.gmt? #=> true
Returns the offset in seconds between the timezone of time and UTC.
t = Time.gm(2000,1,1,20,15,1) #=> 2000-01-01 20:15:01 UTC t.gmt_offset #=> 0 l = t.getlocal #=> 2000-01-01 14:15:01 -0600 l.gmt_offset #=> -21600
Converts time to UTC (GMT), modifying the receiver.
t = Time.now #=> 2007-11-19 08:18:31 -0600 t.gmt? #=> false t.gmtime #=> 2007-11-19 14:18:31 UTC t.gmt? #=> true t = Time.now #=> 2007-11-19 08:18:51 -0600 t.utc? #=> false t.utc #=> 2007-11-19 14:18:51 UTC t.utc? #=> true
Returns the offset in seconds between the timezone of time and UTC.
t = Time.gm(2000,1,1,20,15,1) #=> 2000-01-01 20:15:01 UTC t.gmt_offset #=> 0 l = t.getlocal #=> 2000-01-01 14:15:01 -0600 l.gmt_offset #=> -21600
Returns a hash code for this Time object.
See also Object#hash.
Returns the hour of the day (0..23) for time.
t = Time.now #=> 2007-11-19 08:26:20 -0600 t.hour #=> 8
Returns a detailed string representing time. Unlike #to_s, preserves nanoseconds in the representation for easier debugging.
t = Time.now t.inspect #=> "2012-11-10 18:16:12.261257655 +0100" t.strftime "%Y-%m-%d %H:%M:%S.%N %z" #=> "2012-11-10 18:16:12.261257655 +0100" t.utc.inspect #=> "2012-11-10 17:16:12.261257655 UTC" t.strftime "%Y-%m-%d %H:%M:%S.%N UTC" #=> "2012-11-10 17:16:12.261257655 UTC"
Returns true if time occurs during Daylight Saving Time in its time zone.
# CST6CDT: Time.local(2000, 1, 1).zone #=> "CST" Time.local(2000, 1, 1).isdst #=> false Time.local(2000, 1, 1).dst? #=> false Time.local(2000, 7, 1).zone #=> "CDT" Time.local(2000, 7, 1).isdst #=> true Time.local(2000, 7, 1).dst? #=> true # Asia/Tokyo: Time.local(2000, 1, 1).zone #=> "JST" Time.local(2000, 1, 1).isdst #=> false Time.local(2000, 1, 1).dst? #=> false Time.local(2000, 7, 1).zone #=> "JST" Time.local(2000, 7, 1).isdst #=> false Time.local(2000, 7, 1).dst? #=> false
Converts time to local time (using the local time zone in effect at the creation time of time) modifying the receiver.
If utc_offset is given, it is used instead of the local time.
t = Time.utc(2000, "jan", 1, 20, 15, 1) #=> 2000-01-01 20:15:01 UTC
t.utc? #=> true
t.localtime #=> 2000-01-01 14:15:01 -0600
t.utc? #=> false
t.localtime("+09:00") #=> 2000-01-02 05:15:01 +0900
t.utc? #=> false
If utc_offset is not given and time is local time,
just returns the receiver.
Returns the day of the month (1..n) for time.
t = Time.now #=> 2007-11-19 08:27:03 -0600 t.day #=> 19 t.mday #=> 19
Returns the minute of the hour (0..59) for time.
t = Time.now #=> 2007-11-19 08:25:51 -0600 t.min #=> 25
Returns the month of the year (1..12) for time.
t = Time.now #=> 2007-11-19 08:27:30 -0600 t.mon #=> 11 t.month #=> 11
Returns true if time represents Monday.
t = Time.local(2003, 8, 4) #=> 2003-08-04 00:00:00 -0500 t.monday? #=> true
Returns the month of the year (1..12) for time.
t = Time.now #=> 2007-11-19 08:27:30 -0600 t.mon #=> 11 t.month #=> 11
Returns the number of nanoseconds for time.
t = Time.now #=> 2007-11-17 15:18:03 +0900 "%10.9f" % t.to_f #=> "1195280283.536151409" t.nsec #=> 536151406
The lowest digits of to_f and nsec are different because IEEE 754 double is not accurate enough to represent the exact number of nanoseconds since the Epoch.
The more accurate value is returned by nsec.
Rounds sub seconds to a given precision in decimal digits (0 digits by
default). It returns a new Time object.
ndigits should be zero or a positive integer.
require 'time' t = Time.utc(2010,3,30, 5,43,25.123456789r) t.iso8601(10) #=> "2010-03-30T05:43:25.1234567890Z" t.round.iso8601(10) #=> "2010-03-30T05:43:25.0000000000Z" t.round(0).iso8601(10) #=> "2010-03-30T05:43:25.0000000000Z" t.round(1).iso8601(10) #=> "2010-03-30T05:43:25.1000000000Z" t.round(2).iso8601(10) #=> "2010-03-30T05:43:25.1200000000Z" t.round(3).iso8601(10) #=> "2010-03-30T05:43:25.1230000000Z" t.round(4).iso8601(10) #=> "2010-03-30T05:43:25.1235000000Z" t = Time.utc(1999,12,31, 23,59,59) (t + 0.4).round.iso8601(3) #=> "1999-12-31T23:59:59.000Z" (t + 0.49).round.iso8601(3) #=> "1999-12-31T23:59:59.000Z" (t + 0.5).round.iso8601(3) #=> "2000-01-01T00:00:00.000Z" (t + 1.4).round.iso8601(3) #=> "2000-01-01T00:00:00.000Z" (t + 1.49).round.iso8601(3) #=> "2000-01-01T00:00:00.000Z" (t + 1.5).round.iso8601(3) #=> "2000-01-01T00:00:01.000Z" t = Time.utc(1999,12,31, 23,59,59) (t + 0.123456789).round(4).iso8601(6) #=> "1999-12-31T23:59:59.123500Z"
Returns true if time represents Saturday.
t = Time.local(2006, 6, 10) #=> 2006-06-10 00:00:00 -0500 t.saturday? #=> true
Returns the second of the minute (0..60) for time.
Note: Seconds range from zero to 60 to allow the system to inject leap seconds. See en.wikipedia.org/wiki/Leap_second for further details.
t = Time.now #=> 2007-11-19 08:25:02 -0600 t.sec #=> 2
Formats time according to the directives in the given format string.
The directives begin with a percent (%) character. Any text not listed as a directive will be passed through to the output string.
The directive consists of a percent (%) character, zero or more flags, optional minimum field width, optional modifier and a conversion specifier as follows:
%<flags><width><modifier><conversion>
Flags:
- don't pad a numerical output _ use spaces for padding 0 use zeros for padding ^ upcase the result string # change case : use colons for %z
The minimum field width specifies the minimum width.
The modifiers are “E” and “O”. They are ignored.
Format directives:
Date (Year, Month, Day):
%Y - Year with century if provided, will pad result at least 4 digits.
-0001, 0000, 1995, 2009, 14292, etc.
%C - year / 100 (rounded down such as 20 in 2009)
%y - year % 100 (00..99)
%m - Month of the year, zero-padded (01..12)
%_m blank-padded ( 1..12)
%-m no-padded (1..12)
%B - The full month name (``January'')
%^B uppercased (``JANUARY'')
%b - The abbreviated month name (``Jan'')
%^b uppercased (``JAN'')
%h - Equivalent to %b
%d - Day of the month, zero-padded (01..31)
%-d no-padded (1..31)
%e - Day of the month, blank-padded ( 1..31)
%j - Day of the year (001..366)
Time (Hour, Minute, Second, Subsecond):
%H - Hour of the day, 24-hour clock, zero-padded (00..23)
%k - Hour of the day, 24-hour clock, blank-padded ( 0..23)
%I - Hour of the day, 12-hour clock, zero-padded (01..12)
%l - Hour of the day, 12-hour clock, blank-padded ( 1..12)
%P - Meridian indicator, lowercase (``am'' or ``pm'')
%p - Meridian indicator, uppercase (``AM'' or ``PM'')
%M - Minute of the hour (00..59)
%S - Second of the minute (00..60)
%L - Millisecond of the second (000..999)
The digits under millisecond are truncated to not produce 1000.
%N - Fractional seconds digits, default is 9 digits (nanosecond)
%3N millisecond (3 digits)
%6N microsecond (6 digits)
%9N nanosecond (9 digits)
%12N picosecond (12 digits)
%15N femtosecond (15 digits)
%18N attosecond (18 digits)
%21N zeptosecond (21 digits)
%24N yoctosecond (24 digits)
The digits under the specified length are truncated to avoid
carry up.
Time zone:
%z - Time zone as hour and minute offset from UTC (e.g. +0900)
%:z - hour and minute offset from UTC with a colon (e.g. +09:00)
%::z - hour, minute and second offset from UTC (e.g. +09:00:00)
%Z - Abbreviated time zone name or similar information. (OS dependent)
Weekday:
%A - The full weekday name (``Sunday'')
%^A uppercased (``SUNDAY'')
%a - The abbreviated name (``Sun'')
%^a uppercased (``SUN'')
%u - Day of the week (Monday is 1, 1..7)
%w - Day of the week (Sunday is 0, 0..6)
ISO 8601 week-based year and week number:
The first week of YYYY starts with a Monday and includes YYYY-01-04.
The days in the year before the first week are in the last week of
the previous year.
%G - The week-based year
%g - The last 2 digits of the week-based year (00..99)
%V - Week number of the week-based year (01..53)
Week number:
The first week of YYYY that starts with a Sunday or Monday (according to %U
or %W). The days in the year before the first week are in week 0.
%U - Week number of the year. The week starts with Sunday. (00..53)
%W - Week number of the year. The week starts with Monday. (00..53)
Seconds since the Epoch:
%s - Number of seconds since 1970-01-01 00:00:00 UTC.
Literal string:
%n - Newline character (\n)
%t - Tab character (\t)
%% - Literal ``%'' character
Combination:
%c - date and time (%a %b %e %T %Y)
%D - Date (%m/%d/%y)
%F - The ISO 8601 date format (%Y-%m-%d)
%v - VMS date (%e-%^b-%4Y)
%x - Same as %D
%X - Same as %T
%r - 12-hour time (%I:%M:%S %p)
%R - 24-hour time (%H:%M)
%T - 24-hour time (%H:%M:%S)
This method is similar to strftime() function defined in ISO C and POSIX.
While all directives are locale independent since Ruby 1.9, %Z is platform dependent. So, the result may differ even if the same format string is used in other systems such as C.
%z is recommended over %Z. %Z doesn’t identify the timezone. For example, “CST” is used at America/Chicago (-06:00), America/Havana (-05:00), Asia/Harbin (+08:00), Australia/Darwin (+09:30) and Australia/Adelaide (+10:30). Also, %Z is highly dependent on the operating system. For example, it may generate a non ASCII string on Japanese Windows, i.e. the result can be different to “JST”. So the numeric time zone offset, %z, is recommended.
Examples:
t = Time.new(2007,11,19,8,37,48,"-06:00") #=> 2007-11-19 08:37:48 -0600
t.strftime("Printed on %m/%d/%Y") #=> "Printed on 11/19/2007"
t.strftime("at %I:%M %p") #=> "at 08:37 AM"
Various ISO 8601 formats:
%Y%m%d => 20071119 Calendar date (basic) %F => 2007-11-19 Calendar date (extended) %Y-%m => 2007-11 Calendar date, reduced accuracy, specific month %Y => 2007 Calendar date, reduced accuracy, specific year %C => 20 Calendar date, reduced accuracy, specific century %Y%j => 2007323 Ordinal date (basic) %Y-%j => 2007-323 Ordinal date (extended) %GW%V%u => 2007W471 Week date (basic) %G-W%V-%u => 2007-W47-1 Week date (extended) %GW%V => 2007W47 Week date, reduced accuracy, specific week (basic) %G-W%V => 2007-W47 Week date, reduced accuracy, specific week (extended) %H%M%S => 083748 Local time (basic) %T => 08:37:48 Local time (extended) %H%M => 0837 Local time, reduced accuracy, specific minute (basic) %H:%M => 08:37 Local time, reduced accuracy, specific minute (extended) %H => 08 Local time, reduced accuracy, specific hour %H%M%S,%L => 083748,000 Local time with decimal fraction, comma as decimal sign (basic) %T,%L => 08:37:48,000 Local time with decimal fraction, comma as decimal sign (extended) %H%M%S.%L => 083748.000 Local time with decimal fraction, full stop as decimal sign (basic) %T.%L => 08:37:48.000 Local time with decimal fraction, full stop as decimal sign (extended) %H%M%S%z => 083748-0600 Local time and the difference from UTC (basic) %T%:z => 08:37:48-06:00 Local time and the difference from UTC (extended) %Y%m%dT%H%M%S%z => 20071119T083748-0600 Date and time of day for calendar date (basic) %FT%T%:z => 2007-11-19T08:37:48-06:00 Date and time of day for calendar date (extended) %Y%jT%H%M%S%z => 2007323T083748-0600 Date and time of day for ordinal date (basic) %Y-%jT%T%:z => 2007-323T08:37:48-06:00 Date and time of day for ordinal date (extended) %GW%V%uT%H%M%S%z => 2007W471T083748-0600 Date and time of day for week date (basic) %G-W%V-%uT%T%:z => 2007-W47-1T08:37:48-06:00 Date and time of day for week date (extended) %Y%m%dT%H%M => 20071119T0837 Calendar date and local time (basic) %FT%R => 2007-11-19T08:37 Calendar date and local time (extended) %Y%jT%H%MZ => 2007323T0837Z Ordinal date and UTC of day (basic) %Y-%jT%RZ => 2007-323T08:37Z Ordinal date and UTC of day (extended) %GW%V%uT%H%M%z => 2007W471T0837-0600 Week date and local time and difference from UTC (basic) %G-W%V-%uT%R%:z => 2007-W47-1T08:37-06:00 Week date and local time and difference from UTC (extended)
Returns the fraction for time.
The return value can be a rational number.
t = Time.now #=> 2009-03-26 22:33:12 +0900 "%10.9f" % t.to_f #=> "1238074392.940563917" t.subsec #=> (94056401/100000000)
The lowest digits of to_f and subsec are different because IEEE 754 double is not accurate enough to represent the rational number.
The more accurate value is returned by subsec.
Returns true if time represents Sunday.
t = Time.local(1990, 4, 1) #=> 1990-04-01 00:00:00 -0600 t.sunday? #=> true
Returns true if time represents Thursday.
t = Time.local(1995, 12, 21) #=> 1995-12-21 00:00:00 -0600 t.thursday? #=> true
Returns a ten-element array of values for time:
[sec, min, hour, day, month, year, wday, yday, isdst, zone]
See the individual methods for an explanation of the valid ranges of each value. The ten elements can be passed directly to ::utc or ::local to create a new Time object.
t = Time.now #=> 2007-11-19 08:36:01 -0600 now = t.to_a #=> [1, 36, 8, 19, 11, 2007, 1, 323, false, "CST"]
Returns the value of time as a floating point number of seconds since the Epoch.
t = Time.now "%10.5f" % t.to_f #=> "1270968744.77658" t.to_i #=> 1270968744
Note that IEEE 754 double is not accurate enough to represent the exact number of nanoseconds since the Epoch.
Returns the value of time as an integer number of seconds since the Epoch.
t = Time.now "%10.5f" % t.to_f #=> "1270968656.89607" t.to_i #=> 1270968656
Returns the value of time as a rational number of seconds since the Epoch.
t = Time.now t.to_r #=> (1270968792716287611/1000000000)
This methods is intended to be used to get an accurate value representing the nanoseconds since the Epoch. You can use this method to convert time to another Epoch.
Returns a string representing time. Equivalent to calling strftime with the appropriate format string.
t = Time.now t.to_s #=> "2012-11-10 18:16:12 +0100" t.strftime "%Y-%m-%d %H:%M:%S %z" #=> "2012-11-10 18:16:12 +0100" t.utc.to_s #=> "2012-11-10 17:16:12 UTC" t.strftime "%Y-%m-%d %H:%M:%S UTC" #=> "2012-11-10 17:16:12 UTC"
Returns true if time represents Tuesday.
t = Time.local(1991, 2, 19) #=> 1991-02-19 00:00:00 -0600 t.tuesday? #=> true
Returns the number of nanoseconds for time.
t = Time.now #=> 2007-11-17 15:18:03 +0900 "%10.9f" % t.to_f #=> "1195280283.536151409" t.nsec #=> 536151406
The lowest digits of to_f and nsec are different because IEEE 754 double is not accurate enough to represent the exact number of nanoseconds since the Epoch.
The more accurate value is returned by nsec.
Returns the value of time as an integer number of seconds since the Epoch.
t = Time.now "%10.5f" % t.to_f #=> "1270968656.89607" t.to_i #=> 1270968656
Returns the number of microseconds for time.
t = Time.now #=> 2007-11-19 08:03:26 -0600 "%10.6f" % t.to_f #=> "1195481006.775195" t.usec #=> 775195
Returns the number of microseconds for time.
t = Time.now #=> 2007-11-19 08:03:26 -0600 "%10.6f" % t.to_f #=> "1195481006.775195" t.usec #=> 775195
Converts time to UTC (GMT), modifying the receiver.
t = Time.now #=> 2007-11-19 08:18:31 -0600 t.gmt? #=> false t.gmtime #=> 2007-11-19 14:18:31 UTC t.gmt? #=> true t = Time.now #=> 2007-11-19 08:18:51 -0600 t.utc? #=> false t.utc #=> 2007-11-19 14:18:51 UTC t.utc? #=> true
Returns true if time represents a time in UTC (GMT).
t = Time.now #=> 2007-11-19 08:15:23 -0600 t.utc? #=> false t = Time.gm(2000,"jan",1,20,15,1) #=> 2000-01-01 20:15:01 UTC t.utc? #=> true t = Time.now #=> 2007-11-19 08:16:03 -0600 t.gmt? #=> false t = Time.gm(2000,1,1,20,15,1) #=> 2000-01-01 20:15:01 UTC t.gmt? #=> true
Returns the offset in seconds between the timezone of time and UTC.
t = Time.gm(2000,1,1,20,15,1) #=> 2000-01-01 20:15:01 UTC t.gmt_offset #=> 0 l = t.getlocal #=> 2000-01-01 14:15:01 -0600 l.gmt_offset #=> -21600
Returns an integer representing the day of the week, 0..6, with Sunday == 0.
t = Time.now #=> 2007-11-20 02:35:35 -0600 t.wday #=> 2 t.sunday? #=> false t.monday? #=> false t.tuesday? #=> true t.wednesday? #=> false t.thursday? #=> false t.friday? #=> false t.saturday? #=> false
Returns true if time represents Wednesday.
t = Time.local(1993, 2, 24) #=> 1993-02-24 00:00:00 -0600 t.wednesday? #=> true
Returns an integer representing the day of the year, 1..366.
t = Time.now #=> 2007-11-19 08:32:31 -0600 t.yday #=> 323
Returns the year for time (including the century).
t = Time.now #=> 2007-11-19 08:27:51 -0600 t.year #=> 2007
Returns the name of the time zone used for time. As of Ruby 1.8, returns “UTC” rather than “GMT” for UTC times.
t = Time.gm(2000, "jan", 1, 20, 15, 1) t.zone #=> "UTC" t = Time.local(2000, "jan", 1, 20, 15, 1) t.zone #=> "CST"
Additional notes
There are two Time classes. There's one that is part of core Ruby and there is an additional Time class that is part of the standard library.
The standard library Time class extends the core Time class by adding some methods. If you are using the standard library Time class and cannot find documentation for a method, look at the API docs for the core Time class.
Common questions
Q: Given some number of seconds, how can that be converted into minutes and remainder seconds?
A: There are a few ways. Assume we start with 1234 seconds.
Time.at(1234).strftime "%M:%S" # This returns a String
If you want numerical values, you can do some basic math:
m, s = 1234/60, 1234%60
That second example may be a little too terse for general use. You can wrap it in a method:
def minutes_and_remainder_seconds seconds
[seconds/60, seconds%60]
end
minutes, seconds = *minutes_and_remainder_seconds(1234)
You may want to make this available to multiple classes. You can put it in a module ...
module TimeUtilities
def minutes_and_remainder_seconds seconds
[seconds/60, seconds%60]
end
end
... and then include that module in those classes that use it:
class Foo
include TimeUtilities
# additional class stuff ....
end
Thanks to Andrey Andreevich Ostapchuck and J Bolton for their suggestions on this.
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