View Source NaiveDateTime (Elixir v1.10.3)
A NaiveDateTime struct (without a time zone) and functions.
The NaiveDateTime struct contains the fields year, month, day, hour,
minute, second, microsecond and calendar. New naive datetimes can be
built with the new/2 and new/8 functions or using the
~N (see Kernel.sigil_N/2) sigil:
iex> ~N[2000-01-01 23:00:07]
~N[2000-01-01 23:00:07]The date and time fields in the struct can be accessed directly:
iex> naive = ~N[2000-01-01 23:00:07]
iex> naive.year
2000
iex> naive.second
7We call them "naive" because this datetime representation does not have a time zone. This means the datetime may not actually exist in certain areas in the world even though it is valid.
For example, when daylight saving changes are applied by a region,
the clock typically moves forward or backward by one hour. This means
certain datetimes never occur or may occur more than once. Since
NaiveDateTime is not validated against a time zone, such errors
would go unnoticed.
Developers should avoid creating the NaiveDateTime structs directly and instead, rely on the functions provided by this module as well as the ones in third-party calendar libraries.
Comparing naive date times
Comparisons in Elixir using ==/2, >/2, </2 and similar are structural
and based on the NaiveDateTime struct fields. For proper comparison
between naive datetimes, use the compare/2 function.
Using epochs
The add/3 and diff/3 functions can be used for computing with
date times or retrieving the number of seconds between instants.
For example, if there is an interest in computing the number of
seconds from the Unix epoch (1970-01-01 00:00:00):
iex> NaiveDateTime.diff(~N[2010-04-17 14:00:00], ~N[1970-01-01 00:00:00])
1271512800
iex> NaiveDateTime.add(~N[1970-01-01 00:00:00], 1_271_512_800)
~N[2010-04-17 14:00:00]Those functions are optimized to deal with common epochs, such as the Unix Epoch above or the Gregorian Epoch (0000-01-01 00:00:00).
Link to this section Summary
Functions
Adds a specified amount of time to a NaiveDateTime.
Compares two NaiveDateTime structs.
Converts the given naive_datetime from one calendar to another.
Converts the given naive_datetime from one calendar to another.
Subtracts naive_datetime2 from naive_datetime1.
Converts an Erlang datetime tuple to a NaiveDateTime struct.
Converts an Erlang datetime tuple to a NaiveDateTime struct.
Parses the extended "Date and time of day" format described by ISO 8601:2004.
Parses the extended "Date and time of day" format described by ISO 8601:2004.
Returns the "local time" for the machine the Elixir program is running on.
Builds a naive datetime from date and time structs.
Builds a new ISO naive datetime.
Converts a NaiveDateTime into a Date.
Converts a NaiveDateTime struct to an Erlang datetime tuple.
Converts the given naive datetime to ISO 8601:2004.
Converts the given naive datetime to a string according to its calendar.
Converts a NaiveDateTime into Time.
Returns the given naive datetime with the microsecond field truncated to the
given precision (:microsecond, :millisecond or :second).
Returns the current naive datetime in UTC.
Link to this section Types
@type t() :: %NaiveDateTime{ calendar: Calendar.calendar(), day: Calendar.day(), hour: Calendar.hour(), microsecond: Calendar.microsecond(), minute: Calendar.minute(), month: Calendar.month(), second: Calendar.second(), year: Calendar.year() }
Link to this section Functions
@spec add(Calendar.naive_datetime(), integer(), System.time_unit()) :: t()
Adds a specified amount of time to a NaiveDateTime.
Accepts an amount_to_add in any unit available from System.time_unit/0.
Negative values will move backwards in time.
Examples
# adds seconds by default
iex> NaiveDateTime.add(~N[2014-10-02 00:29:10], 2)
~N[2014-10-02 00:29:12]
# accepts negative offsets
iex> NaiveDateTime.add(~N[2014-10-02 00:29:10], -2)
~N[2014-10-02 00:29:08]
# can work with other units
iex> NaiveDateTime.add(~N[2014-10-02 00:29:10], 2_000, :millisecond)
~N[2014-10-02 00:29:12]
# keeps the same precision
iex> NaiveDateTime.add(~N[2014-10-02 00:29:10.021], 21, :second)
~N[2014-10-02 00:29:31.021]
# changes below the precision will not be visible
iex> hidden = NaiveDateTime.add(~N[2014-10-02 00:29:10], 21, :millisecond)
iex> hidden.microsecond # ~N[2014-10-02 00:29:10]
{21000, 0}
# from Gregorian seconds
iex> NaiveDateTime.add(~N[0000-01-01 00:00:00], 63_579_428_950)
~N[2014-10-02 00:29:10]Passing a DateTime automatically converts it to NaiveDateTime,
discarding the time zone information:
iex> dt = %DateTime{year: 2000, month: 2, day: 29, zone_abbr: "CET",
...> hour: 23, minute: 0, second: 7, microsecond: {0, 0},
...> utc_offset: 3600, std_offset: 0, time_zone: "Europe/Warsaw"}
iex> NaiveDateTime.add(dt, 21, :second)
~N[2000-02-29 23:00:28]@spec compare(Calendar.naive_datetime(), Calendar.naive_datetime()) :: :lt | :eq | :gt
Compares two NaiveDateTime structs.
Returns :gt if first is later than the second
and :lt for vice versa. If the two NaiveDateTime
are equal :eq is returned.
Examples
iex> NaiveDateTime.compare(~N[2016-04-16 13:30:15], ~N[2016-04-28 16:19:25])
:lt
iex> NaiveDateTime.compare(~N[2016-04-16 13:30:15.1], ~N[2016-04-16 13:30:15.01])
:gtThis function can also be used to compare a DateTime without the time zone information:
iex> dt = %DateTime{year: 2000, month: 2, day: 29, zone_abbr: "CET",
...> hour: 23, minute: 0, second: 7, microsecond: {0, 0},
...> utc_offset: 3600, std_offset: 0, time_zone: "Europe/Warsaw"}
iex> NaiveDateTime.compare(dt, ~N[2000-02-29 23:00:07])
:eq
iex> NaiveDateTime.compare(dt, ~N[2000-01-29 23:00:07])
:gt
iex> NaiveDateTime.compare(dt, ~N[2000-03-29 23:00:07])
:lt@spec convert(Calendar.naive_datetime(), Calendar.calendar()) :: {:ok, t()} | {:error, :incompatible_calendars}
Converts the given naive_datetime from one calendar to another.
If it is not possible to convert unambiguously between the calendars
(see Calendar.compatible_calendars?/2), an {:error, :incompatible_calendars} tuple
is returned.
Examples
Imagine someone implements Calendar.Holocene, a calendar based on the
Gregorian calendar that adds exactly 10,000 years to the current Gregorian
year:
iex> NaiveDateTime.convert(~N[2000-01-01 13:30:15], Calendar.Holocene)
{:ok, %NaiveDateTime{calendar: Calendar.Holocene, year: 12000, month: 1, day: 1,
hour: 13, minute: 30, second: 15, microsecond: {0, 0}}}@spec convert!(Calendar.naive_datetime(), Calendar.calendar()) :: t()
Converts the given naive_datetime from one calendar to another.
If it is not possible to convert unambiguously between the calendars
(see Calendar.compatible_calendars?/2), an ArgumentError is raised.
Examples
Imagine someone implements Calendar.Holocene, a calendar based on the
Gregorian calendar that adds exactly 10,000 years to the current Gregorian
year:
iex> NaiveDateTime.convert!(~N[2000-01-01 13:30:15], Calendar.Holocene)
%NaiveDateTime{calendar: Calendar.Holocene, year: 12000, month: 1, day: 1,
hour: 13, minute: 30, second: 15, microsecond: {0, 0}}diff(naive_datetime1, naive_datetime2, unit \\ :second)
View Source (since 1.4.0)@spec diff(Calendar.naive_datetime(), Calendar.naive_datetime(), System.time_unit()) :: integer()
Subtracts naive_datetime2 from naive_datetime1.
The answer can be returned in any unit available from System.time_unit/0.
This function returns the difference in seconds where seconds are measured
according to Calendar.ISO.
Examples
iex> NaiveDateTime.diff(~N[2014-10-02 00:29:12], ~N[2014-10-02 00:29:10])
2
iex> NaiveDateTime.diff(~N[2014-10-02 00:29:12], ~N[2014-10-02 00:29:10], :microsecond)
2_000_000
iex> NaiveDateTime.diff(~N[2014-10-02 00:29:10.042], ~N[2014-10-02 00:29:10.021], :millisecond)
21
iex> NaiveDateTime.diff(~N[2014-10-02 00:29:10], ~N[2014-10-02 00:29:12])
-2
iex> NaiveDateTime.diff(~N[-0001-10-02 00:29:10], ~N[-0001-10-02 00:29:12])
-2
# to Gregorian seconds
iex> NaiveDateTime.diff(~N[2014-10-02 00:29:10], ~N[0000-01-01 00:00:00])
63579428950@spec from_erl(:calendar.datetime(), Calendar.microsecond(), Calendar.calendar()) :: {:ok, t()} | {:error, atom()}
Converts an Erlang datetime tuple to a NaiveDateTime struct.
Attempting to convert an invalid ISO calendar date will produce an error tuple.
Examples
iex> NaiveDateTime.from_erl({{2000, 1, 1}, {13, 30, 15}})
{:ok, ~N[2000-01-01 13:30:15]}
iex> NaiveDateTime.from_erl({{2000, 1, 1}, {13, 30, 15}}, {5000, 3})
{:ok, ~N[2000-01-01 13:30:15.005]}
iex> NaiveDateTime.from_erl({{2000, 13, 1}, {13, 30, 15}})
{:error, :invalid_date}
iex> NaiveDateTime.from_erl({{2000, 13, 1}, {13, 30, 15}})
{:error, :invalid_date}@spec from_erl!(:calendar.datetime(), Calendar.microsecond(), Calendar.calendar()) :: t()
Converts an Erlang datetime tuple to a NaiveDateTime struct.
Raises if the datetime is invalid. Attempting to convert an invalid ISO calendar date will produce an error tuple.
Examples
iex> NaiveDateTime.from_erl!({{2000, 1, 1}, {13, 30, 15}})
~N[2000-01-01 13:30:15]
iex> NaiveDateTime.from_erl!({{2000, 1, 1}, {13, 30, 15}}, {5000, 3})
~N[2000-01-01 13:30:15.005]
iex> NaiveDateTime.from_erl!({{2000, 13, 1}, {13, 30, 15}})
** (ArgumentError) cannot convert {{2000, 13, 1}, {13, 30, 15}} to naive datetime, reason: :invalid_date@spec from_iso8601(String.t(), Calendar.calendar()) :: {:ok, t()} | {:error, atom()}
Parses the extended "Date and time of day" format described by ISO 8601:2004.
Time zone offset may be included in the string but they will be simply discarded as such information is not included in naive date times.
As specified in the standard, the separator "T" may be omitted if desired as there is no ambiguity within this function.
The year parsed by this function is limited to four digits and, while ISO 8601 allows datetimes to specify 24:00:00 as the zero hour of the next day, this notation is not supported by Elixir. Note leap seconds are not supported by the built-in Calendar.ISO.
Examples
iex> NaiveDateTime.from_iso8601("2015-01-23 23:50:07")
{:ok, ~N[2015-01-23 23:50:07]}
iex> NaiveDateTime.from_iso8601("2015-01-23T23:50:07")
{:ok, ~N[2015-01-23 23:50:07]}
iex> NaiveDateTime.from_iso8601("2015-01-23T23:50:07Z")
{:ok, ~N[2015-01-23 23:50:07]}
iex> NaiveDateTime.from_iso8601("2015-01-23 23:50:07.0")
{:ok, ~N[2015-01-23 23:50:07.0]}
iex> NaiveDateTime.from_iso8601("2015-01-23 23:50:07,0123456")
{:ok, ~N[2015-01-23 23:50:07.012345]}
iex> NaiveDateTime.from_iso8601("2015-01-23 23:50:07.0123456")
{:ok, ~N[2015-01-23 23:50:07.012345]}
iex> NaiveDateTime.from_iso8601("2015-01-23T23:50:07.123Z")
{:ok, ~N[2015-01-23 23:50:07.123]}
iex> NaiveDateTime.from_iso8601("2015-01-23P23:50:07")
{:error, :invalid_format}
iex> NaiveDateTime.from_iso8601("2015:01:23 23-50-07")
{:error, :invalid_format}
iex> NaiveDateTime.from_iso8601("2015-01-23 23:50:07A")
{:error, :invalid_format}
iex> NaiveDateTime.from_iso8601("2015-01-23 23:50:61")
{:error, :invalid_time}
iex> NaiveDateTime.from_iso8601("2015-01-32 23:50:07")
{:error, :invalid_date}
iex> NaiveDateTime.from_iso8601("2015-01-23T23:50:07.123+02:30")
{:ok, ~N[2015-01-23 23:50:07.123]}
iex> NaiveDateTime.from_iso8601("2015-01-23T23:50:07.123+00:00")
{:ok, ~N[2015-01-23 23:50:07.123]}
iex> NaiveDateTime.from_iso8601("2015-01-23T23:50:07.123-02:30")
{:ok, ~N[2015-01-23 23:50:07.123]}
iex> NaiveDateTime.from_iso8601("2015-01-23T23:50:07.123-00:00")
{:error, :invalid_format}
iex> NaiveDateTime.from_iso8601("2015-01-23T23:50:07.123-00:60")
{:error, :invalid_format}
iex> NaiveDateTime.from_iso8601("2015-01-23T23:50:07.123-24:00")
{:error, :invalid_format}@spec from_iso8601!(String.t(), Calendar.calendar()) :: t()
Parses the extended "Date and time of day" format described by ISO 8601:2004.
Raises if the format is invalid.
Examples
iex> NaiveDateTime.from_iso8601!("2015-01-23T23:50:07.123Z")
~N[2015-01-23 23:50:07.123]
iex> NaiveDateTime.from_iso8601!("2015-01-23T23:50:07,123Z")
~N[2015-01-23 23:50:07.123]
iex> NaiveDateTime.from_iso8601!("2015-01-23P23:50:07")
** (ArgumentError) cannot parse "2015-01-23P23:50:07" as naive datetime, reason: :invalid_format@spec local_now(Calendar.calendar()) :: t()
Returns the "local time" for the machine the Elixir program is running on.
WARNING: This function can cause insidious bugs. It depends on the time zone configuration at run time. This can changed and be set to a time zone that has daylight saving jumps (spring forward or fall back).
This function can be used to display what the time is right now for the time zone configuration that the machine happens to have. An example would be a desktop program displaying a clock to the user. For any other uses it is probably a bad idea to use this function.
For most cases, use DateTime.now/2 or DateTime.utc_now/1 instead.
Does not include fractional seconds.
Examples
iex> naive_datetime = NaiveDateTime.local_now()
iex> naive_datetime.year >= 2019
trueBuilds a naive datetime from date and time structs.
Examples
iex> NaiveDateTime.new(~D[2010-01-13], ~T[23:00:07.005])
{:ok, ~N[2010-01-13 23:00:07.005]}new(year, month, day, hour, minute, second, microsecond \\ {0, 0}, calendar \\ Calendar.ISO)
View Source@spec new( Calendar.year(), Calendar.month(), Calendar.day(), Calendar.hour(), Calendar.minute(), Calendar.second(), Calendar.microsecond() | non_neg_integer(), Calendar.calendar() ) :: {:ok, t()} | {:error, atom()}
Builds a new ISO naive datetime.
Expects all values to be integers. Returns {:ok, naive_datetime}
if each entry fits its appropriate range, returns {:error, reason}
otherwise.
Examples
iex> NaiveDateTime.new(2000, 1, 1, 0, 0, 0)
{:ok, ~N[2000-01-01 00:00:00]}
iex> NaiveDateTime.new(2000, 13, 1, 0, 0, 0)
{:error, :invalid_date}
iex> NaiveDateTime.new(2000, 2, 29, 0, 0, 0)
{:ok, ~N[2000-02-29 00:00:00]}
iex> NaiveDateTime.new(2000, 2, 30, 0, 0, 0)
{:error, :invalid_date}
iex> NaiveDateTime.new(2001, 2, 29, 0, 0, 0)
{:error, :invalid_date}
iex> NaiveDateTime.new(2000, 1, 1, 23, 59, 59, {0, 1})
{:ok, ~N[2000-01-01 23:59:59.0]}
iex> NaiveDateTime.new(2000, 1, 1, 23, 59, 59, 999_999)
{:ok, ~N[2000-01-01 23:59:59.999999]}
iex> NaiveDateTime.new(2000, 1, 1, 24, 59, 59, 999_999)
{:error, :invalid_time}
iex> NaiveDateTime.new(2000, 1, 1, 23, 60, 59, 999_999)
{:error, :invalid_time}
iex> NaiveDateTime.new(2000, 1, 1, 23, 59, 60, 999_999)
{:error, :invalid_time}
iex> NaiveDateTime.new(2000, 1, 1, 23, 59, 59, 1_000_000)
{:error, :invalid_time}
iex> NaiveDateTime.new(2000, 1, 1, 23, 59, 59, {0, 1}, Calendar.ISO)
{:ok, ~N[2000-01-01 23:59:59.0]}@spec to_date(Calendar.naive_datetime()) :: Date.t()
Converts a NaiveDateTime into a Date.
Because Date does not hold time information,
data will be lost during the conversion.
Examples
iex> NaiveDateTime.to_date(~N[2002-01-13 23:00:07])
~D[2002-01-13]@spec to_erl(Calendar.naive_datetime()) :: :calendar.datetime()
Converts a NaiveDateTime struct to an Erlang datetime tuple.
Only supports converting naive datetimes which are in the ISO calendar, attempting to convert naive datetimes from other calendars will raise.
WARNING: Loss of precision may occur, as Erlang time tuples only store hour/minute/second.
Examples
iex> NaiveDateTime.to_erl(~N[2000-01-01 13:30:15])
{{2000, 1, 1}, {13, 30, 15}}This function can also be used to convert a DateTime to an Erlang datetime tuple without the time zone information:
iex> dt = %DateTime{year: 2000, month: 2, day: 29, zone_abbr: "CET",
...> hour: 23, minute: 0, second: 7, microsecond: {0, 0},
...> utc_offset: 3600, std_offset: 0, time_zone: "Europe/Warsaw"}
iex> NaiveDateTime.to_erl(dt)
{{2000, 2, 29}, {23, 00, 07}}@spec to_iso8601(Calendar.naive_datetime(), :basic | :extended) :: String.t()
Converts the given naive datetime to ISO 8601:2004.
By default, NaiveDateTime.to_iso8601/2 returns naive datetimes formatted in the "extended"
format, for human readability. It also supports the "basic" format through passing the :basic option.
Only supports converting naive datetimes which are in the ISO calendar, attempting to convert naive datetimes from other calendars will raise.
Examples
iex> NaiveDateTime.to_iso8601(~N[2000-02-28 23:00:13])
"2000-02-28T23:00:13"
iex> NaiveDateTime.to_iso8601(~N[2000-02-28 23:00:13.001])
"2000-02-28T23:00:13.001"
iex> NaiveDateTime.to_iso8601(~N[2000-02-28 23:00:13.001], :basic)
"20000228T230013.001"This function can also be used to convert a DateTime to ISO 8601 without the time zone information:
iex> dt = %DateTime{year: 2000, month: 2, day: 29, zone_abbr: "CET",
...> hour: 23, minute: 0, second: 7, microsecond: {0, 0},
...> utc_offset: 3600, std_offset: 0, time_zone: "Europe/Warsaw"}
iex> NaiveDateTime.to_iso8601(dt)
"2000-02-29T23:00:07"@spec to_string(Calendar.naive_datetime()) :: String.t()
Converts the given naive datetime to a string according to its calendar.
Examples
iex> NaiveDateTime.to_string(~N[2000-02-28 23:00:13])
"2000-02-28 23:00:13"
iex> NaiveDateTime.to_string(~N[2000-02-28 23:00:13.001])
"2000-02-28 23:00:13.001"
iex> NaiveDateTime.to_string(~N[-0100-12-15 03:20:31])
"-0100-12-15 03:20:31"This function can also be used to convert a DateTime to a string without the time zone information:
iex> dt = %DateTime{year: 2000, month: 2, day: 29, zone_abbr: "CET",
...> hour: 23, minute: 0, second: 7, microsecond: {0, 0},
...> utc_offset: 3600, std_offset: 0, time_zone: "Europe/Warsaw"}
iex> NaiveDateTime.to_string(dt)
"2000-02-29 23:00:07"@spec to_time(Calendar.naive_datetime()) :: Time.t()
Converts a NaiveDateTime into Time.
Because Time does not hold date information,
data will be lost during the conversion.
Examples
iex> NaiveDateTime.to_time(~N[2002-01-13 23:00:07])
~T[23:00:07]Returns the given naive datetime with the microsecond field truncated to the
given precision (:microsecond, :millisecond or :second).
The given naive datetime is returned unchanged if it already has lower precision than the given precision.
Examples
iex> NaiveDateTime.truncate(~N[2017-11-06 00:23:51.123456], :microsecond)
~N[2017-11-06 00:23:51.123456]
iex> NaiveDateTime.truncate(~N[2017-11-06 00:23:51.123456], :millisecond)
~N[2017-11-06 00:23:51.123]
iex> NaiveDateTime.truncate(~N[2017-11-06 00:23:51.123456], :second)
~N[2017-11-06 00:23:51]@spec utc_now(Calendar.calendar()) :: t()
Returns the current naive datetime in UTC.
Prefer using DateTime.utc_now/0 when possible as, opposite
to NaiveDateTime, it will keep the time zone information.
Examples
iex> naive_datetime = NaiveDateTime.utc_now()
iex> naive_datetime.year >= 2016
true