NaiveDateTime

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 date times can be built with the new/7 function or using the ~N sigil:

iex> ~N[2000-01-01 23:00:07]
~N[2000-01-01 23:00:07]

Both new/7 and sigil return a struct where the date fields can be accessed directly:

iex> naive = ~N[2000-01-01 23:00:07]
iex> naive.year
2000
iex> naive.second
7

The naive bit implies this datetime representation does not have a timezone. 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 timezone, such errors would go unnoticed.

Developers should avoid creating the NaiveDateTime struct directly and instead rely on the functions provided by this module as well as the ones in 3rd party calendar libraries.

Summary

Types

t()

Functions

from_erl(arg, microsecond \\ {0, 0}): Converts an Erlang datetime tuple to a NaiveDateTime struct
from_erl!(tuple, microsecond \\ {0, 0}): Converts an Erlang datetime tuple to a NaiveDateTime struct
from_iso8601(arg): Parses the extended “Date and time of day” format described by ISO8601:2004
from_iso8601!(string): Parses the extended “Date and time of day” format described by ISO8601:2004
new(date, time): Builds a naive date time from date and time structs
new(year, month, day, hour, minute, second, microsecond \\ {0, 0}): Builds a new ISO naive date time
to_date(naive_date_time): Converts a NaiveDateTime into a Date
to_erl(naive_date_time): Converts a NaiveDateTime struct to an Erlang datetime tuple
to_iso8601(naive): Converts the given naive date time to ISO8601
to_string(naive): Converts the given naive date time to a string according to its calendar
to_time(naive_date_time): Converts a NaiveDateTime into Time

Types

t()

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}

Functions

from_erl(arg, microsecond \\ {0, 0})

from_erl(:calendar.datetime, Calendar.microsecond) ::
  {:ok, NaiveDateTime.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}

from_erl!(tuple, microsecond \\ {0, 0})

from_erl!(:calendar.datetime, Calendar.microsecond) ::
  NaiveDateTime.t |
  no_return

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 date time, reason: :invalid_date

from_iso8601(arg)

from_iso8601(String.t) ::
  {:ok, NaiveDateTime.t} |
  {:error, atom}

Parses the extended “Date and time of day” format described by ISO8601:2004.

Timezone 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.

Time representations with reduced accuracy are not supported.

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("2015-01-23T23:50:07.123Z")
{: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}

from_iso8601!(string)

from_iso8601!(String.t) :: NaiveDateTime.t | no_return

Parses the extended “Date and time of day” format described by ISO8601:2004.

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!("2015-01-23P23:50:07")
** (ArgumentError) cannot parse "2015-01-23P23:50:07" as naive date time, reason: :invalid_format

new(date, time)

new(Date.t, Time.t) :: {:ok, NaiveDateTime.t}

Builds a naive date time 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})

new(Calendar.year, Calendar.month, Calendar.day, Calendar.hour, Calendar.minute, Calendar.second, Calendar.microsecond) ::
  {:ok, NaiveDateTime.t} |
  {:error, atom}

Builds a new ISO naive date time.

Expects all values to be integers. Returns {:ok, naive_date_time} 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, 23, 59, 60, 999_999)
{:ok, ~N[2000-01-01 23:59:60.999999]}
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, 61, 999_999)
{:error, :invalid_time}
iex> NaiveDateTime.new(2000, 1, 1, 23, 59, 59, 1_000_000)
{:error, :invalid_time}

to_date(naive_date_time)

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]

to_erl(naive_date_time)

to_erl(NaiveDateTime.t) :: :calendar.datetime

Converts a NaiveDateTime struct to an Erlang datetime tuple.

Only supports converting naive date times which are in the ISO calendar, attempting to convert naive date times 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}}

to_iso8601(naive)

to_iso8601(NaiveDateTime.t) :: String.t

Converts the given naive date time to ISO8601.

Only supports converting naive date times which are in the ISO calendar, attempting to convert naive date times 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"

to_string(naive)

to_string(NaiveDateTime.t) :: String.t

Converts the given naive date time 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"

to_time(naive_date_time)

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]