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Class: Time

Relationships & Source Files
Super Chains via Extension / Inclusion / Inheritance
Instance Chain:
self, ::Comparable
Inherits: Object
Defined in: time.c

Overview

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 Time.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 is 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

Class Method Summary

Instance Attribute Summary

Instance Method Summary

::Comparable - Included

#<

Compares two objects based on the receiver's #<=> method, returning true if it returns -1.
#<=

Compares two objects based on the receiver's #<=> method, returning true if it returns -1 or 0.
#==

Compares two objects based on the receiver's #<=> method, returning true if it returns 0.
#>

Compares two objects based on the receiver's #<=> method, returning true if it returns 1.
#>=

Compares two objects based on the receiver's #<=> method, returning true if it returns 0 or 1.
#between?

Returns false if obj #<=> min is less than zero or if anObject #<=> max is greater than zero, true otherwise.

Constructor Details

.new ⇒ Time .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

Class Method Details

.at(time) ⇒ Time .at(seconds_with_frac) ⇒ Time .at(seconds, microseconds_with_frac) ⇒ 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

.utc(year) ⇒ Time .utc(year, month) ⇒ Time .utc(year, month, day) ⇒ Time .utc(year, month, day, hour) ⇒ Time .utc(year, month, day, hour, min) ⇒ Time .utc(year, month, day, hour, min, sec_with_frac) ⇒ Time .utc(year, month, day, hour, min, sec, usec_with_frac) ⇒ Time .utc(sec, min, hour, day, month, year, dummy, dummy, dummy, dummy) ⇒ Time .gm(year) ⇒ Time .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
Also known as: .utc

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

.local(year) ⇒ Time .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 .mktime(year) ⇒ Time .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
Also known as: .mktime

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

.local(year) ⇒ Time .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 .mktime(year) ⇒ Time .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

Alias for .local.

.now ⇒ Time

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

.utc(year) ⇒ Time .utc(year, month) ⇒ Time .utc(year, month, day) ⇒ Time .utc(year, month, day, hour) ⇒ Time .utc(year, month, day, hour, min) ⇒ Time .utc(year, month, day, hour, min, sec_with_frac) ⇒ Time .utc(year, month, day, hour, min, sec, usec_with_frac) ⇒ Time .utc(sec, min, hour, day, month, year, dummy, dummy, dummy, dummy) ⇒ Time .gm(year) ⇒ Time .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

Alias for .gm.

Instance Attribute Details

#isdst ⇒ Boolean (readonly) #dst? ⇒ Boolean
Also known as: #isdst

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

#friday? ⇒ Boolean (readonly)

Returns true if time represents Friday.

t = Time.local(1987, 12, 18)     #=> 1987-12-18 00:00:00 -0600
t.friday?                        #=> true

#utc? ⇒ Boolean (readonly) #gmt? ⇒ Boolean
Also known as: #utc?

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

#isdst ⇒ Boolean (readonly) #dst? ⇒ Boolean

Alias for #dst?.

#monday? ⇒ Boolean (readonly)

Returns true if time represents Monday.

t = Time.local(2003, 8, 4)       #=> 2003-08-04 00:00:00 -0500
p t.monday?                      #=> true

#saturday? ⇒ Boolean (readonly)

Returns true if time represents Saturday.

t = Time.local(2006, 6, 10)      #=> 2006-06-10 00:00:00 -0500
t.saturday?                      #=> true

#sunday? ⇒ Boolean (readonly)

Returns true if time represents Sunday.

t = Time.local(1990, 4, 1)       #=> 1990-04-01 00:00:00 -0600
t.sunday?                        #=> true

#thursday? ⇒ Boolean (readonly)

Returns true if time represents Thursday.

t = Time.local(1995, 12, 21)     #=> 1995-12-21 00:00:00 -0600
p t.thursday?                    #=> true

#tuesday? ⇒ Boolean (readonly)

Returns true if time represents Tuesday.

t = Time.local(1991, 2, 19)      #=> 1991-02-19 00:00:00 -0600
p t.tuesday?                     #=> true

#utc? ⇒ Boolean (readonly) #gmt? ⇒ Boolean

Alias for #gmt?.

#wednesday? ⇒ Boolean (readonly)

Returns true if time represents Wednesday.

t = Time.local(1993, 2, 24)      #=> 1993-02-24 00:00:00 -0600
p t.wednesday?                   #=> true

Instance Method Details

#+(numeric) ⇒ Time

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

#-(other_time) ⇒ Float #-(numeric) ⇒ Time

Difference — Returns a new Time object that represents the difference 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

#<=>(other_time) ⇒ 1, ...

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

#asctime ⇒ String #ctime ⇒ String

Alias for #ctime.

#asctime ⇒ String #ctime ⇒ String
Also known as: #asctime

Returns a canonical string representation of time.

Time.now.asctime   #=> "Wed Apr  9 08:56:03 2003"

#day ⇒ Fixnum #mday ⇒ Fixnum
Also known as: #mday

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

#eql?(other_time)

Returns true if time and other_time are both Time objects with the same seconds and fractional seconds.

#getgm ⇒ Time #getutc ⇒ Time
Also known as: #getutc

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

#getlocal ⇒ Time #getlocal(utc_offset) ⇒ Time

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.

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

#getgm ⇒ Time #getutc ⇒ Time

Alias for #getgm.

#gmt_offset ⇒ Fixnum #gmtoff ⇒ Fixnum #utc_offset ⇒ Fixnum

Alias for #gmtoff.

#gmtime ⇒ Time #utc ⇒ Time

Alias for #utc.

#gmt_offset ⇒ Fixnum #gmtoff ⇒ Fixnum #utc_offset ⇒ Fixnum
Also known as: #gmt_offset, #utc_offset

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

#hash ⇒ Fixnum

Returns a hash code for this Time object.

See also Object#hash.

#hour ⇒ Fixnum

Returns the hour of the day (0..23) for time.

t = Time.now   #=> 2007-11-19 08:26:20 -0600
t.hour         #=> 8

#inspect ⇒ String #to_s ⇒ String

Alias for #to_s.

#localtime ⇒ Time #localtime(utc_offset) ⇒ Time

Converts time to local time (using the local time zone in effect for this process) 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

#day ⇒ Fixnum #mday ⇒ Fixnum

Alias for #day.

#min ⇒ Fixnum

Returns the minute of the hour (0..59) for time.

t = Time.now   #=> 2007-11-19 08:25:51 -0600
t.min          #=> 25

#mon ⇒ Fixnum #month ⇒ Fixnum
Also known as: #month

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

#mon ⇒ Fixnum #month ⇒ Fixnum

Alias for #mon.

#nsec ⇒ Integer #tv_nsec ⇒ Integer
Also known as: #tv_nsec

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.

#round([ndigits]) ⇒ Time

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 positive integer.

require 'time'

t = Time.utc(2010,3,30, 5,43,"25.123456789".to_r)
p t.iso8601(10)           #=> "2010-03-30T05:43:25.1234567890Z"
p t.round.iso8601(10)     #=> "2010-03-30T05:43:25.0000000000Z"
p t.round(0).iso8601(10)  #=> "2010-03-30T05:43:25.0000000000Z"
p t.round(1).iso8601(10)  #=> "2010-03-30T05:43:25.1000000000Z"
p t.round(2).iso8601(10)  #=> "2010-03-30T05:43:25.1200000000Z"
p t.round(3).iso8601(10)  #=> "2010-03-30T05:43:25.1230000000Z"
p t.round(4).iso8601(10)  #=> "2010-03-30T05:43:25.1235000000Z"
p t.round(5).iso8601(10)  #=> "2010-03-30T05:43:25.1234600000Z"
p t.round(6).iso8601(10)  #=> "2010-03-30T05:43:25.1234570000Z"
p t.round(7).iso8601(10)  #=> "2010-03-30T05:43:25.1234568000Z"
p t.round(8).iso8601(10)  #=> "2010-03-30T05:43:25.1234567900Z"
p t.round(9).iso8601(10)  #=> "2010-03-30T05:43:25.1234567890Z"
p t.round(10).iso8601(10) #=> "2010-03-30T05:43:25.1234567890Z"

t = Time.utc(1999,12,31, 23,59,59)
p((t + 0.4).round.iso8601(3))    #=> "1999-12-31T23:59:59.000Z"
p((t + 0.49).round.iso8601(3))   #=> "1999-12-31T23:59:59.000Z"
p((t + 0.5).round.iso8601(3))    #=> "2000-01-01T00:00:00.000Z"
p((t + 1.4).round.iso8601(3))    #=> "2000-01-01T00:00:00.000Z"
p((t + 1.49).round.iso8601(3))   #=> "2000-01-01T00:00:00.000Z"
p((t + 1.5).round.iso8601(3))    #=> "2000-01-01T00:00:01.000Z"

t = Time.utc(1999,12,31, 23,59,59)
p (t + 0.123456789).round(4).iso8601(6)  #=> "1999-12-31T23:59:59.123500Z"

#sec ⇒ Fixnum

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

#strftime(string) ⇒ String

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 08:37AM"

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)

#subsec ⇒ Numeric

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.

#succ ⇒ Time

Returns a new Time object, one second later than time. succ is obsolete since 1.9.2 for time is not a discrete value.

t = Time.now       #=> 2007-11-19 08:23:57 -0600
t.succ             #=> 2007-11-19 08:23:58 -0600

Use instead time + 1

t + 1              #=> 2007-11-19 08:23:58 -0600

#to_a ⇒ Array

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"]

#to_f ⇒ Float

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 number of nanoseconds since the Epoch.

#to_i ⇒ Integer #tv_sec ⇒ Integer
Also known as: #tv_sec

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

#to_r ⇒ Rational

Returns the value of time as a rational number of seconds since the Epoch.

t = Time.now
p 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.

#inspect ⇒ String #to_s ⇒ String
Also known as: #inspect

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"

#nsec ⇒ Integer #tv_nsec ⇒ Integer

Alias for #nsec.

#to_i ⇒ Integer #tv_sec ⇒ Integer

Alias for #to_i.

#usec ⇒ Integer #tv_usec ⇒ Integer

Alias for #usec.

#usec ⇒ Integer #tv_usec ⇒ Integer
Also known as: #tv_usec

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

#gmtime ⇒ Time (readonly) #utc ⇒ Time
Also known as: #gmtime

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

#gmt_offset ⇒ Fixnum #gmtoff ⇒ Fixnum #utc_offset ⇒ Fixnum

Alias for #gmtoff.

#wday ⇒ Fixnum

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

#yday ⇒ Fixnum

Returns an integer representing the day of the year, 1..366.

t = Time.now   #=> 2007-11-19 08:32:31 -0600
t.yday         #=> 323

#year ⇒ Fixnum

Returns the year for time (including the century).

t = Time.now   #=> 2007-11-19 08:27:51 -0600
t.year         #=> 2007

#zone ⇒ String

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"