struct Time
Overview
Time
represents a date-time instant in incremental time observed in a specific time zone.
The calendaric calculations are based on the rules of the proleptic Gregorian calendar as specified in ISO 8601. Leap seconds are ignored.
Internally, the time is stored as an Int64
representing seconds from epoch (0001-01-01 00:00:00.0 UTC
) and an Int32
representing nanosecond-of-second with value range 0..999_999_999
.
The supported date range is 0001-01-01 00:00:00.0
to 9999-12-31 23:59:59.999_999_999
in any local time zone.
Telling the Time
There are several methods to retrieve a Time
instance representing the current time:
Time.utc # returns the current time in UTC Time.local Time::Location.load("Europe/Berlin") # returns the current time in time zone Europe/Berlin Time.local # returns the current time in current time zone
It is generally recommended to keep instances in UTC and only apply a local time zone when formatting for user display, unless the domain logic requires having a specific time zone (for example for calendaric operations).
Creating a Specific Instant
Time
instances representing a specific instant can be created by .utc
or .new
with the date-time specified as individual arguments:
time = Time.utc(2016, 2, 15, 10, 20, 30) time.to_s # => 2016-02-15 10:20:30 UTC time = Time.local(2016, 2, 15, 10, 20, 30, location: Time::Location.load("Europe/Berlin")) time.to_s # => 2016-02-15 10:20:30 +01:00 Europe/Berlin # The time-of-day can be omitted and defaults to midnight (start of day): time = Time.utc(2016, 2, 15) time.to_s # => 2016-02-15 00:00:00 UTC
Retrieving Time Information
Each Time
instance allows querying calendar data:
time = Time.utc(2016, 2, 15, 10, 20, 30) time.year # => 2016 time.month # => 2 time.day # => 15 time.hour # => 10 time.minute # => 20 time.second # => 30 time.millisecond # => 0 time.nanosecond # => 0 time.day_of_week # => Time::DayOfWeek::Monday time.day_of_year # => 46 time.monday? # => true time.time_of_day # => 10:20:30
For querying if a time is at a specific day of week, Time
offers named predicate methods, delegating to #day_of_week
:
time.monday? # => true # ... time.sunday? # => false
Time Zones
Each time is attached to a specific time zone, represented by a Location
(see #location
). #zone
returns the time zone observed in this location at the current time (i.e. the instant represented by this Time
). #offset
returns the offset of the current zone in seconds.
time = Time.local(2018, 3, 8, 22, 5, 13, location: Time::Location.load("Europe/Berlin")) time # => 2018-03-08 22:05:13 +01:00 Europe/Berlin time.location # => #<Time::Location Europe/Berlin> time.zone # => #<Time::Location::Zone CET +01:00 (3600s) STD> time.offset # => 3600
Using .utc
, the location is Time::Location::UTC
:
time = Time.utc(2018, 3, 8, 22, 5, 13) time # => 2018-03-08 22:05:13.0 UTC time.location # => #<Time::Location UTC> time.zone # => #<Time::Location::Zone UTC +00:00 (0s) STD> time.offset # => 0
A Time
instance can be transformed to a different time zone while retaining the same instant using #in
:
time_de = Time.local(2018, 3, 8, 22, 5, 13, location: Time::Location.load("Europe/Berlin")) time_ar = time_de.in Time::Location.load("America/Buenos_Aires") time_de # => 2018-03-08 22:05:13 +01:00 Europe/Berlin time_ar # => 2018-03-08 18:05:13 -03:00 America/Buenos_Aires
Both Time
instances show a different local date-time, but they represent the same date-time in the instant time-line, therefore they are considered equal:
time_de.to_utc # => 2018-03-08 21:05:13 UTC time_ar.to_utc # => 2018-03-08 21:05:13 UTC time_de == time_ar # => true
There are also two special methods for converting to UTC and local time zone:
time.to_utc # equals time.in(Location::UTC) time.to_local # equals time.in(Location.local)
#to_local_in
allows changing the time zone while keeping the same local date-time (wall clock) which results in a different instant on the time line.
Formatting and Parsing Time
To make date-time instances exchangeable between different computer systems or readable to humans, they are usually converted to and from a string representation.
The method #to_s
formats the date-time according to a specified pattern.
time = Time.utc(2015, 10, 12, 10, 30, 0) time.to_s("%Y-%m-%d %H:%M:%S %:z") # => "2015-10-12 10:30:00 +00:00"
Similarly, Time.parse
and Time.parse!
are used to construct a Time
instance from date-time information in a string, according to a specified pattern:
Time.parse("2015-10-12 10:30:00 +00:00", "%Y-%m-%d %H:%M:%S %z", Time::Location::UTC) Time.parse!("2015-10-12 10:30:00 +00:00", "%Y-%m-%d %H:%M:%S %z")
See Time::Format
for all directives.
Calculations
Time.utc(2015, 10, 10) - 5.days # => 2015-10-05 00:00:00 +00:00 span = Time.utc(2015, 10, 10) - Time.utc(2015, 9, 10) span.days # => 30 span.total_hours # => 720 span.total_minutes # => 43200
Measuring Time
The typical time representation provided by the operating system is based on a "wall clock" which is subject to changes for clock synchronization. This can result in discontinuous jumps in the time-line making it not suitable for accurately measuring elapsed time.
Instances of Time
are focused on telling time – using a "wall clock". When Time.local
is called multiple times, the difference between the returned instances is not guaranteed to equal to the time elapsed between making the calls; even the order of the returned Time
instances might not reflect invocation order.
t1 = Time.utc # operation that takes 1 minute t2 = Time.utc t2 - t1 # => ?
The resulting Time::Span
could be anything, even negative, if the computer's wall clock has changed between both calls.
As an alternative, the operating system also provides a monotonic clock. Its time-line has no specified starting point but is strictly linearly increasing.
This monotonic clock should always be used for measuring elapsed time.
A reading from this clock can be taken using .monotonic
:
t1 = Time.monotonic # operation that takes 1 minute t2 = Time.monotonic t2 - t1 # => 1.minute (approximately)
The execution time of a block can be measured using .measure
:
elapsed_time = Time.measure do # operation that takes 20 milliseconds end elapsed_time # => 20.milliseconds (approximately)
Included Modules
Defined in:
json/to_json.crtime.cr
yaml/to_yaml.cr
Constant Summary
- UNIX_EPOCH =
new(unsafe_utc_seconds: 62135596800_i64)
-
This constant is defined to be "1970-01-01 00:00:00 UTC". Can be used to create a
Time::Span
that represents an Unix Epoch time duration.Time.utc - Time::UNIX_EPOCH
Constructors
- .local(year : Int32, month : Int32, day : Int32, hour : Int32 = 0, minute : Int32 = 0, second : Int32 = 0, *, nanosecond : Int32 = 0, location : Location = Location.local) : Time
Creates a new
Time
instance representing the given local date-time in location (defaults to local time zone). - .local(location : Location = Location.local) : Time
Creates a new
Time
instance representing the current time from the system clock observed in location (defaults to local time zone). - .new(ctx : YAML::ParseContext, node : YAML::Nodes::Node)
- .new(pull : JSON::PullParser)
- .new(*, seconds : Int64, nanoseconds : Int32, location : Location)
Creates a new
Time
instance that corresponds to the number of seconds and nanoseconds elapsed from epoch (0001-01-01 00:00:00.0 UTC
) observed in location. - .parse(time : String, pattern : String, location : Location) : Time
Parses a
Time
from time string using the given pattern. - .parse!(time : String, pattern : String) : Time
Parses a
Time
from time string using the given pattern. - .parse_local(time : String, pattern : String) : Time
Parses a
Time
from time string using the given pattern andTime::Location.local
as default location - .parse_rfc2822(time : String) : self
Parse time format specified by RFC 2822.
- .parse_rfc3339(time : String) : self
- .parse_utc(time : String, pattern : String) : Time
Parses a
Time
from time string using the given pattern andTime::Location::UTC
as default location. - .unix(seconds : Int) : Time
Creates a new
Time
instance that corresponds to the number of seconds elapsed since the Unix epoch (1970-01-01 00:00:00 UTC
). - .unix_ms(milliseconds : Int) : Time
Creates a new
Time
instance that corresponds to the number of milliseconds elapsed since the Unix epoch (1970-01-01 00:00:00 UTC
). - .utc(year : Int32, month : Int32, day : Int32, hour : Int32 = 0, minute : Int32 = 0, second : Int32 = 0, *, nanosecond : Int32 = 0) : Time
Creates a new
Time
instance representing the given date-time in UTC. - .utc : Time
Creates a new
Time
instance representing the current time from the system clock in UTC. - .utc(*, seconds : Int64, nanoseconds : Int32) : Time
Creates a new
Time
instance that corresponds to the number of seconds and nanoseconds elapsed from epoch (0001-01-01 00:00:00.0 UTC
) in UTC. - .week_date(year : Int32, week : Int32, day_of_week : Int32 | DayOfWeek, hour : Int32 = 0, minute : Int32 = 0, second : Int32 = 0, *, nanosecond : Int32 = 0, location : Location = Location.local) : self
Creates an instance specified by a commercial week date consisting of ISO calendar year, week and a day_of_week.
Class Method Summary
- .days_in_month(year : Int, month : Int) : Int32
Returns the number of days in month (value range:
1..12
) taking account of the year. - .days_in_year(year : Int) : Int32
Returns the number of days in year.
- .leap_year?(year : Int) : Bool
Returns
true
if year is a leap year in the proleptic Gregorian calendar. - .measure(&) : Time::Span
Measures the execution time of block.
- .monotonic : Time::Span
Returns a reading from the monotonic clock to measure elapsed time.
- .parse_iso8601(time : String)
Parse datetime format specified by ISO 8601.
Instance Method Summary
- #+(span : Time::Span) : Time
Returns a copy of this
Time
with span added. - #+(span : Time::MonthSpan) : Time
Returns a copy of this
Time
with span added. - #-(other : Time) : Time::Span
Returns a
Time::Span
amounting to the duration between other andself
. - #-(span : Time::Span) : Time
Returns a copy of this
Time
with span subtracted. - #-(span : Time::MonthSpan) : Time
Returns a copy of this
Time
with span subtracted. - #<=>(other : Time) : Int32
Compares this
Time
with other. - #==(other : Time) : Bool
Compares this
Time
with other for equality. - #at_beginning_of_day : Time
Returns a copy of this
Time
representing the beginning of the day. - #at_beginning_of_hour : Time
Returns a copy of this
Time
representing the beginning of the hour. - #at_beginning_of_minute : Time
Returns a copy of this
Time
representing the beginning of the minute. - #at_beginning_of_month : Time
Returns a copy of this
Time
representing the beginning of the month. - #at_beginning_of_quarter : Time
Returns a copy of this
Time
representing the beginning of the quarter. - #at_beginning_of_second : Time
Returns a copy of this
Time
representing the beginning of the seconds. - #at_beginning_of_semester : Time
Returns a copy of this
Time
representing the beginning of the semester. - #at_beginning_of_week : Time
Returns a copy of this
Time
representing the beginning of the week. - #at_beginning_of_year : Time
Returns a copy of this
Time
representing the beginning of the year. - #at_end_of_day : Time
Returns a copy of this
Time
representing the end of the day. - #at_end_of_hour : Time
Returns a copy of this
Time
representing the end of the hour. - #at_end_of_minute : Time
Returns a copy of this
Time
representing the end of the minute. - #at_end_of_month : Time
Returns a copy of this
Time
representing the end of the month. - #at_end_of_quarter : Time
Returns a copy of this
Time
representing the end of the quarter. - #at_end_of_second : Time
Returns a copy of this
Time
representing the end of the second. - #at_end_of_semester : Time
Returns a copy of this
Time
representing the end of the semester. - #at_end_of_week : Time
Returns a copy of this
Time
representing the end of the week. - #at_end_of_year : Time
Returns a copy of this
Time
representing the end of the year. - #at_midday : Time
Returns a copy of this
Time
representing midday (12:00
) of the same day. - #calendar_week : Tuple(Int32, Int32)
Returns the ISO calendar year and week in which this instance occurs.
- #clone : Time
- #date : Tuple(Int32, Int32, Int32)
- #day : Int32
Returns the day of the month (
1..31
). - #day_of_week : Time::DayOfWeek
Returns the day of the week (
Monday..Sunday
). - #day_of_year : Int32
Returns the day of the year.
- #friday? : Bool
Returns
true
if the day of week is Friday. - #hash(hasher)
- #hour : Int32
Returns the hour of the day (
0..23
). - #in(location : Location) : Time
Returns a copy of this
Time
representing the same instant observed in location. - #inspect(io : IO, with_nanoseconds = true) : Nil
Prints this
Time
to io. - #local? : Bool
Returns
true
if#location
equals to the local time zone (Time::Location.local
). - #location : Location
- #millisecond : Int32
Returns the millisecond of the second (
0..999
). - #minute : Int32
Returns the minute of the hour (
0..59
). - #monday? : Bool
Returns
true
if the day of week is Monday. - #month : Int32
Returns the month of the year (
1..12
). - #nanosecond : Int32
Returns the nanosecond of the second (
0..999_999_999
). - #offset : Int32
Returns the offset from UTC (in seconds) in effect in
#location
at this instant. - #saturday? : Bool
Returns
true
if the day of week is Saturday. - #second : Int32
Returns the second of the minute (
0..59
). - #shift(seconds : Int, nanoseconds : Int) : Time
Returns a copy of this
Time
shifted by the number of seconds and nanoseconds. - #shift(*, years : Int = 0, months : Int = 0, weeks : Int = 0, days : Int = 0, hours : Int = 0, minutes : Int = 0, seconds : Int = 0, nanoseconds : Int = 0)
Returns a copy of this
Time
shifted by the amount of calendaric units provided as arguments. - #sunday? : Bool
Returns
true
if the day of week is Sunday. - #thursday? : Bool
Returns
true
if the day of week is Thursday. - #time_of_day : Time::Span
Returns the duration between this
Time
and midnight of the same day. - #to_json(json : JSON::Builder) : Nil
- #to_local : Time
Returns a copy of this
Time
representing the same instant in the local time zone (Time::Location.local
). - #to_local_in(location : Location) : Time
Creates a new
Time
instance with the same local date-time representation (wall clock) in a different location. - #to_rfc2822(io : IO)
Format this time using the format specified by RFC 2822 into the given io.
- #to_rfc2822 : String
Format this time using the format specified by RFC 2822.
- #to_rfc3339(io : IO, *, fraction_digits : Int = 0) : Nil
- #to_rfc3339(*, fraction_digits : Int = 0)
- #to_s(io : IO, format : String) : Nil
Formats this
Time
according to the pattern in format to the given io. - #to_s(io : IO) : Nil
Prints this
Time
to io. - #to_s(format : String) : String
Formats this
Time
according to the pattern in format. - #to_unix : Int64
Returns the number of seconds since the Unix epoch (
1970-01-01 00:00:00 UTC
). - #to_unix_f : Float64
Returns the number of seconds since the Unix epoch (
1970-01-01 00:00:00 UTC
) asFloat64
with nanosecond precision. - #to_unix_ms : Int64
Returns the number of milliseconds since the Unix epoch (
1970-01-01 00:00:00 UTC
). - #to_utc : Time
Returns a copy of this
Time
representing the same instant in UTC (Time::Location::UTC
). - #to_yaml(yaml : YAML::Nodes::Builder) : Nil
- #tuesday? : Bool
Returns
true
if the day of week is Tuesday. - #utc? : Bool
Returns
true
if#location
equals toLocation::UTC
. - #wednesday? : Bool
Returns
true
if the day of week is Wednesday. - #year : Int32
Returns the year of the proleptic Georgian Calendar (
0..9999
). - #zone : Time::Location::Zone
Returns the time zone in effect in
#location
at this instant.
Instance methods inherited from module Steppable
step(*, to limit = nil, by step, exclusive : Bool = false, &) : Nilstep(*, to limit = nil, by step, exclusive : Bool = false) step
Instance methods inherited from module Comparable(Time)
<, <=(other : T) <=, <=>(other : T) <=>, ==(other : T) ==, >(other : T) : Bool >, >=(other : T) >=, clamp(min, max)clamp(range : Range) clamp
Instance methods inherited from struct Struct
==(other) : Bool ==, hash(hasher) hash, inspect(io : IO) : Nil inspect, pretty_print(pp) : Nil pretty_print, to_s(io : IO) : Nil to_s Instance methods inherited from struct Value
==(other : JSON::Any)==(other : YAML::Any)
==(other) ==, dup dup
Instance methods inherited from class Object
! : Bool !, !=(other) !=, !~(other) !~, ==(other) ==, ===(other : JSON::Any)===(other : YAML::Any)
===(other) ===, =~(other) =~, as(type : Class) as, as?(type : Class) as?, class class, dup dup, hash(hasher)
hash hash, in?(collection : Object) : Bool
in?(*values : Object) : Bool in?, inspect(io : IO) : Nil
inspect : String inspect, is_a?(type : Class) : Bool is_a?, itself itself, nil? : Bool nil?, not_nil! not_nil!, pretty_inspect(width = 79, newline = "\n", indent = 0) : String pretty_inspect, pretty_print(pp : PrettyPrint) : Nil pretty_print, responds_to?(name : Symbol) : Bool responds_to?, tap(&) tap, to_json(io : IO) : Nil
to_json : String to_json, to_pretty_json(indent : String = " ") : String
to_pretty_json(io : IO, indent : String = " ") : Nil to_pretty_json, to_s(io : IO) : Nil
to_s : String to_s, to_yaml(io : IO) : Nil
to_yaml : String to_yaml, try(&) try, unsafe_as(type : T.class) forall T unsafe_as
Class methods inherited from class Object
from_json(string_or_io, root : String)from_json(string_or_io) from_json, from_yaml(string_or_io : String | IO) from_yaml
Constructor Detail
def self.local(year : Int32, month : Int32, day : Int32, hour : Int32 = 0, minute : Int32 = 0, second : Int32 = 0, *, nanosecond : Int32 = 0, location : Location = Location.local) : TimeSource
Creates a new Time
instance representing the given local date-time in location (defaults to local time zone).
time = Time.local(2016, 2, 15, 10, 20, 30, location: Time::Location.load("Europe/Berlin")) time.inspect # => "2016-02-15 10:20:30.0 +01:00 Europe/Berlin"
Valid value ranges for the individual fields:
-
#year
:1..9999
-
#month
:1..12
-
#day
:1
-28
/29
/30
/31
(depending on month and year) -
#hour
:0..23
-
#minute
:0..59
-
#second
:0..59
-
#nanosecond
:0..999_999_999
The time-of-day can be omitted and defaults to midnight (start of day):
time = Time.utc(2016, 2, 15) time.to_s # => "2016-02-15 00:00:00 UTC"
The local date-time representation is resolved to a single instant based on the offset observed in the location at this time.
This process can sometimes be ambiguous, mostly due skipping or repeating times at time zone transitions. For example, in America/New_York
the date-time 2011-03-13 02:15:00
never occurred, there is a gap between time zones. In return, 2011-11-06 01:15:00
occurred twice because of overlapping time zones.
In such cases, the choice of time zone, and therefore the time, is not well-defined. This method returns a time that is correct in one of the two zones involved in the transition, but it does not guarantee which.
def self.local(location : Location = Location.local) : TimeSource
Creates a new Time
instance representing the current time from the system clock observed in location (defaults to local time zone).
def self.new(ctx : YAML::ParseContext, node : YAML::Nodes::Node)Source
def self.new(pull : JSON::PullParser)Source
def self.new(*, seconds : Int64, nanoseconds : Int32, location : Location)Source
Creates a new Time
instance that corresponds to the number of seconds and nanoseconds elapsed from epoch (0001-01-01 00:00:00.0 UTC
) observed in location.
Valid range for seconds is 0..315_537_897_599
. For nanoseconds it is 0..999_999_999
.
def self.parse(time : String, pattern : String, location : Location) : TimeSource
Parses a Time
from time string using the given pattern.
See Time::Format
for details.
Time.parse("2016-04-05", "%F", Time::Location.load("Europe/Berlin")) # => 2016-04-05 00:00:00.0 +02:00 Europe/Berlin
If there is no time zone information in the formatted time, location will be assumed. When location is nil
, in such a case the parser will raise Time::Format::Error
.
def self.parse!(time : String, pattern : String) : TimeSource
Parses a Time
from time string using the given pattern.
See Time::Format
for details.
Time.parse!("2016-04-05 +00:00", "%F %:z") # => 2016-04-05 00:00:00.0 +00:00 Time.parse!("2016-04-05", "%F") # raises Time::Format::Error
If there is no time zone information in the formatted time, the parser will raise Time::Format::Error
.
def self.parse_local(time : String, pattern : String) : TimeSource
Parses a Time
from time string using the given pattern and Time::Location.local
as default location
See Time::Format
for details.
Time.parse_utc("2016-04-05", "%F") # => 2016-04-05 00:00:00.0 +00:00
Time::Location.local
will only be used as #location
if the formatted time does not contain any time zone information. The return value can't be assumed to be a UTC time (this can be achieved by calling #to_local
).
def self.parse_utc(time : String, pattern : String) : TimeSource
Parses a Time
from time string using the given pattern and Time::Location::UTC
as default location.
See Time::Format
for details.
Time.parse_utc("2016-04-05", "%F") # => 2016-04-05 00:00:00.0 +00:00
Time::Location::UTC
will only be used as #location
if the formatted time does not contain any time zone information. The return value can't be assumed to be a UTC time (this can be achieved by calling #to_utc
).
def self.unix(seconds : Int) : TimeSource
Creates a new Time
instance that corresponds to the number of seconds elapsed since the Unix epoch (1970-01-01 00:00:00 UTC
).
The time zone is always UTC.
Time.unix(981173106) # => 2001-02-03 04:05:06 UTC
def self.unix_ms(milliseconds : Int) : TimeSource
Creates a new Time
instance that corresponds to the number of milliseconds elapsed since the Unix epoch (1970-01-01 00:00:00 UTC
).
The time zone is always UTC.
time = Time.unix_ms(981173106789) # => 2001-02-03 04:05:06.789 UTC time.millisecond # => 789
def self.utc(year : Int32, month : Int32, day : Int32, hour : Int32 = 0, minute : Int32 = 0, second : Int32 = 0, *, nanosecond : Int32 = 0) : TimeSource
Creates a new Time
instance representing the given date-time in UTC.
time = Time.utc(2016, 2, 15, 10, 20, 30) time.to_s # => "2016-02-15 10:20:30 UTC"
Valid value ranges for the individual fields:
-
#year
:1..9999
-
#month
:1..12
-
#day
:1
-28
/29
/30
/31
(depending on month and year) -
#hour
:0..23
-
#minute
:0..59
-
#second
:0..59
-
#nanosecond
:0..999_999_999
The time-of-day can be omitted and defaults to midnight (start of day):
time = Time.utc(2016, 2, 15) time.to_s # => "2016-02-15 00:00:00 UTC"
Since UTC does not have any time zone transitions, each date-time is unambiguously resolved.
def self.utc : TimeSource
Creates a new Time
instance representing the current time from the system clock in UTC.
def self.utc(*, seconds : Int64, nanoseconds : Int32) : TimeSource
Creates a new Time
instance that corresponds to the number of seconds and nanoseconds elapsed from epoch (0001-01-01 00:00:00.0 UTC
) in UTC.
Valid range for seconds is 0..315_537_897_599
. For nanoseconds it is 0..999_999_999
.
def self.week_date(year : Int32, week : Int32, day_of_week : Int32 | DayOfWeek, hour : Int32 = 0, minute : Int32 = 0, second : Int32 = 0, *, nanosecond : Int32 = 0, location : Location = Location.local) : selfSource
Creates an instance specified by a commercial week date consisting of ISO calendar year, week and a day_of_week.
This equates to the results from #calendar_week
and #day_of_week
.
Valid value ranges for the individual fields:
-
#year
:1..9999
-
week
:1..53
-
#day_of_week
:1..7
Class Method Detail
def self.days_in_month(year : Int, month : Int) : Int32Source
Returns the number of days in month (value range: 1..12
) taking account of the year.
The returned value is either 28
, 29
, 30
or 31
depending on the month and whether year is leap.
Time.days_in_month(2016, 2) # => 29 Time.days_in_month(1990, 4) # => 30
def self.days_in_year(year : Int) : Int32Source
Returns the number of days in year.
A normal year has 365
days, a leap year 366
days.
Time.days_in_year(1990) # => 365 Time.days_in_year(2004) # => 366
def self.leap_year?(year : Int) : BoolSource
Returns true
if year is a leap year in the proleptic Gregorian calendar.
def self.measure(&) : Time::SpanSource
Measures the execution time of block.
The measurement relies on the monotonic clock and is not affected by fluctuations of the system clock (see #monotonic
).
elapsed_time = Time.measure do # operation that takes 20 milliseconds end elapsed_time # => 20.milliseconds (approximately)
def self.monotonic : Time::SpanSource
Returns a reading from the monotonic clock to measure elapsed time.
Values from the monotonic clock and wall clock are not comparable. This method does not return a Time
instance but a Time::Span
amounting to the number of nanoseconds elapsed since the unspecified starting point of the monotonic clock. The returned values are strictly linearly increasing.
This clock should be independent from discontinuous jumps in the system time, such as leap seconds, time zone adjustments or manual changes to the computer's clock.
Subtracting two results from this method equals to the time elapsed between both readings:
start = Time.monotonic # operation that takes 20 milliseconds elapsed = Time.monotonic - start # => 20.milliseconds (approximately) # operation that takes 50 milliseconds elapsed_total = Time.monotonic - start # => 70.milliseconds (approximately)
The execution time of a block can be measured using .measure
.
def self.parse_iso8601(time : String)Source
Parse datetime format specified by ISO 8601.
This is similar to .parse_rfc3339
but RFC 3339 defines a more strict format. In ISO 8601 for examples, field delimiters (#-
, :
) are optional.
Use #to_rfc3339
to format a Time
according to .
Instance Method Detail
def +(span : Time::Span) : TimeSource
def +(span : Time::MonthSpan) : TimeSource
Returns a copy of this Time
with span added.
It adds the number of months with overflow increasing the year. If the resulting day-of-month would be invalid, it is adjusted to the last valid day of the month.
For example, adding 1.month
to 2007-03-31
would result in the invalid date 2007-04-31
which will be adjusted to 2007-04-30
.
This operates on the local time-line, such that the local date-time representations of month and year are increased by the specified amount.
If the resulting date-time is ambiguous due to time zone transitions, a correct time will be returned, but it does not guarantee which.
def -(other : Time) : Time::SpanSource
Returns a Time::Span
amounting to the duration between other and self
.
The time span is negative if self
is before other.
The duration amounts to the actual time elapsed between both instances, on the instant time-line. The difference between local date-time representations may equal to a different duration, depending on time zone transitions.
def -(span : Time::Span) : TimeSource
def -(span : Time::MonthSpan) : TimeSource
Returns a copy of this Time
with span subtracted.
It adds the number of months with overflow decreasing the year. If the resulting day-of-month would be invalid, it is adjusted to the last valid day of the month.
For example, subtracting 1.month
from 2007-05-31
would result in the invalid date 2007-04-31
which will be adjusted to 2007-04-30
.
This operates on the local time-line, such that the local date-time representations of month and year are decreased by the specified amount.
If the resulting date-time is ambiguous due to time zone transitions, a correct time will be returned, but it does not guarantee which.
def <=>(other : Time) : Int32Source
Compares this Time
with other.
The comparison is based on the instant time-line, even if the local date-time representation (wall clock) would compare differently.
To ensure the comparison is also true for local wall clock, both date-times need to be transformed to the same time zone.
def ==(other : Time) : BoolSource
Compares this Time
with other for equality.
Two instances are considered equal if they represent the same date-time in the instant time-line, even if they show a different local date-time.
time_de = Time.local(2018, 3, 8, 22, 5, 13, location: Time::Location.load("Europe/Berlin")) time_ar = Time.local(2018, 3, 8, 18, 5, 13, location: Time::Location.load("America/Buenos_Aires")) time_de == time_ar # => true # both times represent the same instant: time_de.to_utc # => 2018-03-08 21:05:13 UTC time_ar.to_utc # => 2018-03-08 21:05:13 UTC
def at_beginning_of_day : TimeSource
Returns a copy of this Time
representing the beginning of the day.
def at_beginning_of_hour : TimeSource
Returns a copy of this Time
representing the beginning of the hour.
def at_beginning_of_minute : TimeSource
Returns a copy of this Time
representing the beginning of the minute.
def at_beginning_of_month : TimeSource
Returns a copy of this Time
representing the beginning of the month.
def at_beginning_of_quarter : TimeSource
Returns a copy of this Time
representing the beginning of the quarter.
def at_beginning_of_second : TimeSource
Returns a copy of this Time
representing the beginning of the seconds.
This essentially resets nanoseconds
to 0.
def at_beginning_of_semester : TimeSource
Returns a copy of this Time
representing the beginning of the semester.
def at_beginning_of_week : TimeSource
Returns a copy of this Time
representing the beginning of the week.
TODO Ensure correctness in local time-line.
def at_beginning_of_year : TimeSource
Returns a copy of this Time
representing the beginning of the year.
def at_end_of_semester : TimeSource
Returns a copy of this Time
representing the end of the semester.
def at_end_of_week : TimeSource
Returns a copy of this Time
representing the end of the week.
TODO Ensure correctness in local time-line.
def calendar_week : Tuple(Int32, Int32)Source
Returns the ISO calendar year and week in which this instance occurs.
The ISO calendar year to which the week belongs is not always in the same as the year of the regular calendar date. The first three days of January sometimes belong to week 52 (or 53) of the previous year; equally the last three days of December sometimes are already in week 1 of the following year.
For that reason, this method returns a tuple year, week
consisting of the calendar year to which the calendar week belongs and the ordinal number of the week within that year.
Together with #day_of_week
this represents a specific day as commercial or week date format year, week, day_of_week
in the same way as the typical format year, month, day
. .week_date
creates a Time
instance from a week date.
def day_of_week : Time::DayOfWeekSource
Returns the day of the week (Monday..Sunday
).
def day_of_year : Int32Source
Returns the day of the year.
The value range is 1..365
in normal years and 1..366
in leap years.
def friday? : BoolSource
Returns true
if the day of week is Friday.
See #day_of_week
for details.
def in(location : Location) : TimeSource
Returns a copy of this Time
representing the same instant observed in location.
This method changes the time zone and retains the instant, which will usually result in a different representation of local date-time (unless both locations have the same offset).
Ambiguous time zone transitions such as gaps and overlaps have no effect on the result because it retains the same instant.
time_de = Time.local(2018, 3, 8, 22, 5, 13, location: Time::Location.load("Europe/Berlin")) time_ar = time_de.in Time::Location.load("America/Buenos_Aires") time_de # => 2018-03-08 22:05:13 +01:00 Europe/Berlin time_ar # => 2018-03-08 18:05:13 -03:00 America/Buenos_Aires
In contrast, #to_local_in
changes to a different location while preserving the same wall time, which results in different instants on the time line.
def inspect(io : IO, with_nanoseconds = true) : NilSource
Prints this Time
to io.
The local date-time is formatted as date string YYYY-MM-DD HH:mm:ss.nnnnnnnnn +ZZ:ZZ:ZZ
. Nanoseconds are omitted if with_nanoseconds is false
. When the location is UTC
, the offset is omitted. Offset seconds are omitted if 0
.
The name of the location is appended unless it is a fixed zone offset.
def local? : BoolSource
Returns true
if #location
equals to the local time zone (Time::Location.local
).
Since the system's settings may change during a program's runtime, the result may not be identical between different invocations.
def monday? : BoolSource
Returns true
if the day of week is Monday.
See #day_of_week
for details.
def offset : Int32Source
Returns the offset from UTC (in seconds) in effect in #location
at this instant.
def saturday? : BoolSource
Returns true
if the day of week is Saturday.
See #day_of_week
for details.
def shift(seconds : Int, nanoseconds : Int) : TimeSource
Returns a copy of this Time
shifted by the number of seconds and nanoseconds.
Positive values result in a later time, negative values in an earlier time.
This operates on the instant time-line, such that adding the equivalent of one hour will always be a duration of one hour later. The local date-time representation may change by a different amount, depending on time zone transitions.
Overflow in nanoseconds will be transferred to seconds.
There is no explicit limit on the input values but the addition must result in a valid time between 0001-01-01 00:00:00.0
and 9999-12-31 23:59:59.999_999_999
. Otherwise ArgumentError
is raised.
def shift(*, years : Int = 0, months : Int = 0, weeks : Int = 0, days : Int = 0, hours : Int = 0, minutes : Int = 0, seconds : Int = 0, nanoseconds : Int = 0)Source
Returns a copy of this Time
shifted by the amount of calendaric units provided as arguments.
Positive values result in a later time, negative values in an earlier time.
This operates on the local time-line, such that the local date-time representation of the result will be apart by the specified amounts, but the elapsed time between both instances might not equal to the combined default duration. This is the case for example when adding a day over a daylight-savings time change:
start = Time.new(2017, 10, 28, 13, 37, location: Time::Location.load("Europe/Berlin")) one_day_later = start.shift days: 1 one_day_later - start # => 25.hours
years is equivalent to 12
months and weeks is equivalent to 7
days.
If the day-of-month resulting from shifting by years and months would be invalid, the date is adjusted to the last valid day of the month. For example, adding one month to 2018-08-31
would result in the invalid date 2018-09-31
which will be adjusted to 2018-09-30
:
Time.utc(2018, 7, 31).shift(months: 1) # => Time.utc(2018, 8, 31) Time.utc(2018, 8, 31).shift(months: 1) # => Time.utc(2018, 9, 30)
Overflow in smaller units is transferred to the next larger unit.
Changes are applied in the same order as the arguments, sorted by increasing granularity. This is relevant because the order of operations can change the result:
Time.utc(2018, 8, 31).shift(months: 1, days: -1) # => Time.utc(2018, 9, 29) Time.utc(2018, 8, 31).shift(months: 1).shift(days: -1) # => Time.utc(2018, 9, 29) Time.utc(2018, 8, 31).shift(days: -1).shift(months: 1) # => Time.utc(2018, 9, 30)
There is no explicit limit on the input values but the shift must result in a valid time between 0001-01-01 00:00:00.0
and 9999-12-31 23:59:59.999_999_999
. Otherwise ArgumentError
is raised.
If the resulting date-time is ambiguous due to time zone transitions, a correct time will be returned, but it does not guarantee which.
def sunday? : BoolSource
Returns true
if the day of week is Sunday.
See #day_of_week
for details.
def thursday? : BoolSource
Returns true
if the day of week is Thursday.
See #day_of_week
for details.
def time_of_day : Time::SpanSource
Returns the duration between this Time
and midnight of the same day.
This is equivalent to creating a Time::Span
from the time-of-day fields:
time.time_of_day == Time::Span.new(hours: time.hour, minutes: time.minute, seconds: time.second, nanoseconds: time.nanosecond)
def to_json(json : JSON::Builder) : NilSource
def to_local : TimeSource
Returns a copy of this Time
representing the same instant in the local time zone (Time::Location.local
).
See #in
for details.
def to_local_in(location : Location) : TimeSource
Creates a new Time
instance with the same local date-time representation (wall clock) in a different location.
Unlike #in
, which always preserves the same instant in time, #to_local_in
adjusts the instant such that it results in the same local date-time representation. Both instants are apart from each other by the difference in zone offsets.
new_year = Time.utc(2019, 1, 1, 0, 0, 0) tokyo = new_year.to_local_in(Time::Location.load("Asia/Tokyo")) new_york = new_year.to_local_in(Time::Location.load("America/New_York")) tokyo.inspect # => "2019-01-01 00:00:00.0 +09:00 Asia/Tokyo" new_york.inspect # => "2019-01-01 00:00:00.0 -05:00 America/New_York"
def to_rfc3339(*, fraction_digits : Int = 0)Source
Format this time using the format specified by RFC 3339 (ISO 8601 profile).
Time.utc(2016, 2, 15).to_rfc3339 # => "2016-02-15T00:00:00Z"
ISO 8601 allows some freedom over the syntax and RFC 3339 exercises that freedom to rigidly define a fixed format intended for use in internet protocols and standards.
Number of seconds decimals can be selected with fraction_digits. Values accepted are 0 (the default, no decimals), 3 (milliseconds), 6 (microseconds) or 9 (nanoseconds).
def to_s(io : IO, format : String) : NilSource
Formats this Time
according to the pattern in format to the given io.
See Time::Format
for details.
def to_s(io : IO) : NilSource
Prints this Time
to io.
The local date-time is formatted as date string YYYY-MM-DD HH:mm:ss +ZZ:ZZ:ZZ
. Nanoseconds are always omitted. When the location is UTC
, the offset is replaced with the string UTC
. Offset seconds are omitted if 0
.
def to_s(format : String) : StringSource
Formats this Time
according to the pattern in format.
See Time::Format
for details.
time = Time.local(2016, 4, 5) time.to_s("%F") # => "2016-04-05"
def to_unix : Int64Source
Returns the number of seconds since the Unix epoch (1970-01-01 00:00:00 UTC
).
time = Time.utc(2016, 1, 12, 3, 4, 5) time.to_unix # => 1452567845
def to_unix_f : Float64Source
Returns the number of seconds since the Unix epoch (1970-01-01 00:00:00 UTC
) as Float64
with nanosecond precision.
time = Time.utc(2016, 1, 12, 3, 4, 5, nanosecond: 678_000_000) time.to_unix_f # => 1452567845.678
def to_unix_ms : Int64Source
Returns the number of milliseconds since the Unix epoch (1970-01-01 00:00:00 UTC
).
time = Time.utc(2016, 1, 12, 3, 4, 5, nanosecond: 678_000_000) time.to_unix_ms # => 1452567845678
def to_utc : TimeSource
Returns a copy of this Time
representing the same instant in UTC (Time::Location::UTC
).
See #in
for details.
def to_yaml(yaml : YAML::Nodes::Builder) : NilSource
def tuesday? : BoolSource
Returns true
if the day of week is Tuesday.
See #day_of_week
for details.
def utc? : BoolSource
Returns true
if #location
equals to Location::UTC
.
def wednesday? : BoolSource
Returns true
if the day of week is Wednesday.
See #day_of_week
for details.
def zone : Time::Location::ZoneSource
Returns the time zone in effect in #location
at this instant.
© 2012–2021 Manas Technology Solutions.
Licensed under the Apache License, Version 2.0.
https://crystal-lang.org/api/1.2.1/Time.html