Calendar.ISO

A calendar implementation that follows to ISO 8601.

This calendar implements the proleptic Gregorian calendar and is therefore compatible with the calendar used in most countries today. The proleptic means the Gregorian rules for leap years are applied for all time, consequently the dates give different results before the year 1583 from when the Gregorian calendar was adopted.

Note that while ISO 8601 allows times and datetimes to specify 24:00:00 as the zero hour of the next day, this notation is not supported by Elixir.

Summary

Types

bce(): "Before the Current Era" or "Before the Common Era" (BCE), for those years less than 1.
ce(): The "Current Era" or the "Common Era" (CE) which starts in year 1.
day()
day_of_week(): Integer that represents the day of the week, where 1 is Monday and 7 is Sunday.
day_of_year()
era(): The calendar era.
hour()
microsecond(): Microseconds with stored precision.
minute()
month()
quarter_of_year()
second()
year()
year_of_era()

Functions

date_to_string(year, month, day, format \\ :extended): Converts the given date into a string.
datetime_to_string(year, month, day, hour, minute, second, microsecond, time_zone, zone_abbr, utc_offset, std_offset, format \\ :extended): Converts the datetime (with time zone) into a string.
day_of_era(year, month, day): Calculates the day and era from the given year, month, and day.
day_of_week(year, month, day): Calculates the day of the week from the given year, month, and day.
day_of_year(year, month, day): Calculates the day of the year from the given year, month, and day.
day_rollover_relative_to_midnight_utc(): See Calendar.day_rollover_relative_to_midnight_utc/0 for documentation.
days_in_month(year, month): Returns how many days there are in the given year-month.
leap_year?(year): Returns if the given year is a leap year.
months_in_year(year): Returns how many months there are in the given year.
naive_datetime_from_iso_days(arg): Converts the Calendar.iso_days/0 format to the datetime format specified by this calendar.
naive_datetime_to_iso_days(year, month, day, hour, minute, second, microsecond): Returns the Calendar.iso_days/0 format of the specified date.
naive_datetime_to_string(year, month, day, hour, minute, second, microsecond, format \\ :extended): Converts the datetime (without time zone) into a string.
parse_date(string): Parses a date string.
parse_naive_datetime(string): Parses a naive datetime string.
parse_time(string): Parses a time string.
parse_utc_datetime(string): Parses a UTC datetime string.
quarter_of_year(year, month, day): Calculates the quarter of the year from the given year, month, and day.
time_from_day_fraction(arg): Converts a day fraction to this Calendar's representation of time.
time_to_day_fraction(hour, minute, second, arg): Returns the normalized day fraction of the specified time.
time_to_string(hour, minute, second, microsecond, format \\ :extended): Converts the given time into a string.
valid_date?(year, month, day): Determines if the date given is valid according to the proleptic Gregorian calendar.
valid_time?(hour, minute, second, microsecond): Determines if the date given is valid according to the proleptic Gregorian calendar.
year_of_era(year): Calculates the year and era from the given year.

Types

bce()

Specs

bce() :: 0

"Before the Current Era" or "Before the Common Era" (BCE), for those years less than 1.

ce()

Specs

ce() :: 1

The "Current Era" or the "Common Era" (CE) which starts in year 1.

day()

Specs

day() :: 1..31

day_of_week()

Specs

day_of_week() :: 1..7

Integer that represents the day of the week, where 1 is Monday and 7 is Sunday.

day_of_year()

Specs

day_of_year() :: 1..366

era()

Specs

era() :: bce() | ce()

The calendar era.

The ISO calendar has two eras:

CE - which starts in year 1 and is defined as era 1.
BCE - for those years less than 1 and is defined as era 0.

hour()

Specs

hour() :: 0..23

microsecond()

Specs

microsecond() :: {0..999_999, 0..6}

Microseconds with stored precision.

The precision represents the number of digits that must be used when representing the microseconds to external format. If the precision is 0, it means microseconds must be skipped.

minute()

Specs

minute() :: 0..59

month()

Specs

month() :: 1..12

quarter_of_year()

Specs

quarter_of_year() :: 1..4

second()

Specs

second() :: 0..59

year()

Specs

year() :: -9999..9999

year_of_era()

Specs

year_of_era() :: {1..10000, era()}

Functions

date_to_string(year, month, day, format \\ :extended)

Specs

date_to_string(year(), month(), day(), :basic | :extended) :: String.t()

Converts the given date into a string.

By default, returns dates formatted in the "extended" format, for human readability. It also supports the "basic" format by passing the :basic option.

Examples

iex> Calendar.ISO.date_to_string(2015, 2, 28)
"2015-02-28"
iex> Calendar.ISO.date_to_string(2017, 8, 1)
"2017-08-01"
iex> Calendar.ISO.date_to_string(-99, 1, 31)
"-0099-01-31"

iex> Calendar.ISO.date_to_string(2015, 2, 28, :basic)
"20150228"
iex> Calendar.ISO.date_to_string(-99, 1, 31, :basic)
"-00990131"

datetime_to_string(year, month, day, hour, minute, second, microsecond, time_zone, zone_abbr, utc_offset, std_offset, format \\ :extended)

Specs

datetime_to_string(
  year(),
  month(),
  day(),
  Calendar.hour(),
  Calendar.minute(),
  Calendar.second(),
  Calendar.microsecond(),
  Calendar.time_zone(),
  Calendar.zone_abbr(),
  Calendar.utc_offset(),
  Calendar.std_offset(),
  :basic | :extended
) :: String.t()

Converts the datetime (with time zone) into a string.

By default, returns datetimes formatted in the "extended" format, for human readability. It also supports the "basic" format by passing the :basic option.

Examples

iex> time_zone = "Etc/UTC"
iex> Calendar.ISO.datetime_to_string(2017, 8, 1, 1, 2, 3, {4, 5}, time_zone, "UTC", 0, 0)
"2017-08-01 01:02:03.00000Z"
iex> Calendar.ISO.datetime_to_string(2017, 8, 1, 1, 2, 3, {4, 5}, time_zone, "UTC", 3600, 0)
"2017-08-01 01:02:03.00000+01:00"
iex> Calendar.ISO.datetime_to_string(2017, 8, 1, 1, 2, 3, {4, 5}, time_zone, "UTC", 3600, 3600)
"2017-08-01 01:02:03.00000+02:00"

iex> time_zone = "Europe/Berlin"
iex> Calendar.ISO.datetime_to_string(2017, 8, 1, 1, 2, 3, {4, 5}, time_zone, "CET", 3600, 0)
"2017-08-01 01:02:03.00000+01:00 CET Europe/Berlin"
iex> Calendar.ISO.datetime_to_string(2017, 8, 1, 1, 2, 3, {4, 5}, time_zone, "CDT", 3600, 3600)
"2017-08-01 01:02:03.00000+02:00 CDT Europe/Berlin"

iex> time_zone = "America/Los_Angeles"
iex> Calendar.ISO.datetime_to_string(2015, 2, 28, 1, 2, 3, {4, 5}, time_zone, "PST", -28800, 0)
"2015-02-28 01:02:03.00000-08:00 PST America/Los_Angeles"
iex> Calendar.ISO.datetime_to_string(2015, 2, 28, 1, 2, 3, {4, 5}, time_zone, "PDT", -28800, 3600)
"2015-02-28 01:02:03.00000-07:00 PDT America/Los_Angeles"

iex> time_zone = "Europe/Berlin"
iex> Calendar.ISO.datetime_to_string(2017, 8, 1, 1, 2, 3, {4, 5}, time_zone, "CET", 3600, 0, :basic)
"20170801 010203.00000+0100 CET Europe/Berlin"

day_of_era(year, month, day)

Specs

day_of_era(year(), month(), day()) :: Calendar.day_of_era()

Calculates the day and era from the given year, month, and day.

Examples

iex> Calendar.ISO.day_of_era(0, 1, 1)
{366, 0}
iex> Calendar.ISO.day_of_era(1, 1, 1)
{1, 1}
iex> Calendar.ISO.day_of_era(0, 12, 31)
{1, 0}
iex> Calendar.ISO.day_of_era(0, 12, 30)
{2, 0}
iex> Calendar.ISO.day_of_era(-1, 12, 31)
{367, 0}

day_of_week(year, month, day)

Specs

day_of_week(year(), month(), day()) :: day_of_week()

Calculates the day of the week from the given year, month, and day.

It is an integer from 1 to 7, where 1 is Monday and 7 is Sunday.

Examples

iex> Calendar.ISO.day_of_week(2016, 10, 31)
1
iex> Calendar.ISO.day_of_week(2016, 11, 1)
2
iex> Calendar.ISO.day_of_week(2016, 11, 2)
3
iex> Calendar.ISO.day_of_week(2016, 11, 3)
4
iex> Calendar.ISO.day_of_week(2016, 11, 4)
5
iex> Calendar.ISO.day_of_week(2016, 11, 5)
6
iex> Calendar.ISO.day_of_week(2016, 11, 6)
7
iex> Calendar.ISO.day_of_week(-99, 1, 31)
4

day_of_year(year, month, day)

Specs

day_of_year(year(), month(), day()) :: day_of_year()

Calculates the day of the year from the given year, month, and day.

It is an integer from 1 to 366.

Examples

iex> Calendar.ISO.day_of_year(2016, 1, 31)
31
iex> Calendar.ISO.day_of_year(-99, 2, 1)
32
iex> Calendar.ISO.day_of_year(2018, 2, 28)
59

day_rollover_relative_to_midnight_utc()

Specs

day_rollover_relative_to_midnight_utc() :: {0, 1}

See Calendar.day_rollover_relative_to_midnight_utc/0 for documentation.

days_in_month(year, month)

Specs

days_in_month(year(), month()) :: 28..31

Returns how many days there are in the given year-month.

Examples

iex> Calendar.ISO.days_in_month(1900, 1)
31
iex> Calendar.ISO.days_in_month(1900, 2)
28
iex> Calendar.ISO.days_in_month(2000, 2)
29
iex> Calendar.ISO.days_in_month(2001, 2)
28
iex> Calendar.ISO.days_in_month(2004, 2)
29
iex> Calendar.ISO.days_in_month(2004, 4)
30
iex> Calendar.ISO.days_in_month(-1, 5)
31

leap_year?(year)

Specs

leap_year?(year()) :: boolean()

Returns if the given year is a leap year.

Examples

iex> Calendar.ISO.leap_year?(2000)
true
iex> Calendar.ISO.leap_year?(2001)
false
iex> Calendar.ISO.leap_year?(2004)
true
iex> Calendar.ISO.leap_year?(1900)
false
iex> Calendar.ISO.leap_year?(-4)
true

months_in_year(year)

Specs

months_in_year(year()) :: 12

Returns how many months there are in the given year.

Example

iex> Calendar.ISO.months_in_year(2004)
12

naive_datetime_from_iso_days(arg)

Specs

naive_datetime_from_iso_days(Calendar.iso_days()) ::
  {Calendar.year(), Calendar.month(), Calendar.day(), Calendar.hour(),
   Calendar.minute(), Calendar.second(), Calendar.microsecond()}

Converts the Calendar.iso_days/0 format to the datetime format specified by this calendar.

Examples

iex> Calendar.ISO.naive_datetime_from_iso_days({0, {0, 86400}})
{0, 1, 1, 0, 0, 0, {0, 6}}
iex> Calendar.ISO.naive_datetime_from_iso_days({730_485, {0, 86400}})
{2000, 1, 1, 0, 0, 0, {0, 6}}
iex> Calendar.ISO.naive_datetime_from_iso_days({730_485, {43200, 86400}})
{2000, 1, 1, 12, 0, 0, {0, 6}}
iex> Calendar.ISO.naive_datetime_from_iso_days({-365, {0, 86400000000}})
{-1, 1, 1, 0, 0, 0, {0, 6}}

naive_datetime_to_iso_days(year, month, day, hour, minute, second, microsecond)

Specs

naive_datetime_to_iso_days(
  Calendar.year(),
  Calendar.month(),
  Calendar.day(),
  Calendar.hour(),
  Calendar.minute(),
  Calendar.second(),
  Calendar.microsecond()
) :: Calendar.iso_days()

Returns the Calendar.iso_days/0 format of the specified date.

Examples

iex> Calendar.ISO.naive_datetime_to_iso_days(0, 1, 1, 0, 0, 0, {0, 6})
{0, {0, 86400000000}}
iex> Calendar.ISO.naive_datetime_to_iso_days(2000, 1, 1, 12, 0, 0, {0, 6})
{730485, {43200000000, 86400000000}}
iex> Calendar.ISO.naive_datetime_to_iso_days(2000, 1, 1, 13, 0, 0, {0, 6})
{730485, {46800000000, 86400000000}}
iex> Calendar.ISO.naive_datetime_to_iso_days(-1, 1, 1, 0, 0, 0, {0, 6})
{-365, {0, 86400000000}}

naive_datetime_to_string(year, month, day, hour, minute, second, microsecond, format \\ :extended)

Specs

naive_datetime_to_string(
  year(),
  month(),
  day(),
  Calendar.hour(),
  Calendar.minute(),
  Calendar.second(),
  Calendar.microsecond(),
  :basic | :extended
) :: String.t()

Converts the datetime (without time zone) into a string.

By default, returns datetimes formatted in the "extended" format, for human readability. It also supports the "basic" format by passing the :basic option.

Examples

iex> Calendar.ISO.naive_datetime_to_string(2015, 2, 28, 1, 2, 3, {4, 6})
"2015-02-28 01:02:03.000004"
iex> Calendar.ISO.naive_datetime_to_string(2017, 8, 1, 1, 2, 3, {4, 5})
"2017-08-01 01:02:03.00000"

iex> Calendar.ISO.naive_datetime_to_string(2015, 2, 28, 1, 2, 3, {4, 6}, :basic)
"20150228 010203.000004"

parse_date(string)

Parses a date string.

Examples

iex> Calendar.ISO.parse_date("2015-01-23")
{:ok, {2015, 1, 23}}
iex> Calendar.ISO.parse_date("-2015-01-23")
{:ok, {-2015, 1, 23}}
iex> Calendar.ISO.parse_date("2015:01:23")
{:error, :invalid_format}
iex> Calendar.ISO.parse_date("2015-01-32")
{:error, :invalid_date}

parse_naive_datetime(string)

Parses a naive datetime string.

Examples

iex> Calendar.ISO.parse_naive_datetime("2015-01-23 23:50:07")
{:ok, {2015, 1, 23, 23, 50, 7, {0, 0}}}
iex> Calendar.ISO.parse_naive_datetime("2015-01-23T23:50:07")
{:ok, {2015, 1, 23, 23, 50, 7, {0, 0}}}
iex> Calendar.ISO.parse_naive_datetime("2015-01-23T23:50:07Z")
{:ok, {2015, 1, 23, 23, 50, 7, {0, 0}}}

iex> Calendar.ISO.parse_naive_datetime("2015-01-23 23:50:07.0")
{:ok, {2015, 1, 23, 23, 50, 7, {0, 1}}}
iex> Calendar.ISO.parse_naive_datetime("2015-01-23 23:50:07,0123456")
{:ok, {2015, 1, 23, 23, 50, 7, {12345, 6}}}
iex> Calendar.ISO.parse_naive_datetime("2015-01-23 23:50:07.0123456")
{:ok, {2015, 1, 23, 23, 50, 7, {12345, 6}}}
iex> Calendar.ISO.parse_naive_datetime("2015-01-23T23:50:07.123Z")
{:ok, {2015, 1, 23, 23, 50, 7, {123000, 3}}}

iex> Calendar.ISO.parse_naive_datetime("2015-01-23P23:50:07")
{:error, :invalid_format}
iex> Calendar.ISO.parse_naive_datetime("2015:01:23 23-50-07")
{:error, :invalid_format}
iex> Calendar.ISO.parse_naive_datetime("2015-01-23 23:50:07A")
{:error, :invalid_format}
iex> Calendar.ISO.parse_naive_datetime("2015-01-23 23:50:61")
{:error, :invalid_time}
iex> Calendar.ISO.parse_naive_datetime("2015-01-32 23:50:07")
{:error, :invalid_date}

iex> Calendar.ISO.parse_naive_datetime("2015-01-23T23:50:07.123+02:30")
{:ok, {2015, 1, 23, 23, 50, 7, {123000, 3}}}
iex> Calendar.ISO.parse_naive_datetime("2015-01-23T23:50:07.123+00:00")
{:ok, {2015, 1, 23, 23, 50, 7, {123000, 3}}}
iex> Calendar.ISO.parse_naive_datetime("2015-01-23T23:50:07.123-02:30")
{:ok, {2015, 1, 23, 23, 50, 7, {123000, 3}}}
iex> Calendar.ISO.parse_naive_datetime("2015-01-23T23:50:07.123-00:00")
{:error, :invalid_format}
iex> Calendar.ISO.parse_naive_datetime("2015-01-23T23:50:07.123-00:60")
{:error, :invalid_format}
iex> Calendar.ISO.parse_naive_datetime("2015-01-23T23:50:07.123-24:00")
{:error, :invalid_format}

parse_time(string)

Parses a time string.

Examples

iex> Calendar.ISO.parse_time("23:50:07")
{:ok, {23, 50, 7, {0, 0}}}
iex> Calendar.ISO.parse_time("23:50:07Z")
{:ok, {23, 50, 7, {0, 0}}}
iex> Calendar.ISO.parse_time("T23:50:07Z")
{:ok, {23, 50, 7, {0, 0}}}

iex> Calendar.ISO.parse_time("23:50:07,0123456")
{:ok, {23, 50, 7, {12345, 6}}}
iex> Calendar.ISO.parse_time("23:50:07.0123456")
{:ok, {23, 50, 7, {12345, 6}}}
iex> Calendar.ISO.parse_time("23:50:07.123Z")
{:ok, {23, 50, 7, {123000, 3}}}

iex> Calendar.ISO.parse_time("2015:01:23 23-50-07")
{:error, :invalid_format}
iex> Calendar.ISO.parse_time("23:50:07A")
{:error, :invalid_format}
iex> Calendar.ISO.parse_time("23:50:07.")
{:error, :invalid_format}
iex> Calendar.ISO.parse_time("23:50:61")
{:error, :invalid_time}

parse_utc_datetime(string)

Parses a UTC datetime string.

Examples

iex> Calendar.ISO.parse_utc_datetime("2015-01-23T23:50:07Z")
{:ok, {2015, 1, 23, 23, 50, 7, {0, 0}}, 0}

iex> Calendar.ISO.parse_utc_datetime("2015-01-23T23:50:07.123+02:30")
{:ok, {2015, 1, 23, 21, 20, 7, {123000, 3}}, 9000}

iex> Calendar.ISO.parse_utc_datetime("2015-01-23T23:50:07,123+02:30")
{:ok, {2015, 1, 23, 21, 20, 7, {123000, 3}}, 9000}

iex> Calendar.ISO.parse_utc_datetime("-2015-01-23T23:50:07Z")
{:ok, {-2015, 1, 23, 23, 50, 7, {0, 0}}, 0}

iex> Calendar.ISO.parse_utc_datetime("-2015-01-23T23:50:07,123+02:30")
{:ok, {-2015, 1, 23, 21, 20, 7, {123000, 3}}, 9000}

iex> Calendar.ISO.parse_utc_datetime("2015-01-23P23:50:07")
{:error, :invalid_format}
iex> Calendar.ISO.parse_utc_datetime("2015-01-23T23:50:07")
{:error, :missing_offset}
iex> Calendar.ISO.parse_utc_datetime("2015-01-23 23:50:61")
{:error, :invalid_time}
iex> Calendar.ISO.parse_utc_datetime("2015-01-32 23:50:07")
{:error, :invalid_date}
iex> Calendar.ISO.parse_utc_datetime("2015-01-23T23:50:07.123-00:00")
{:error, :invalid_format}

quarter_of_year(year, month, day)

Specs

quarter_of_year(year(), month(), day()) :: quarter_of_year()

Calculates the quarter of the year from the given year, month, and day.

It is an integer from 1 to 4.

Examples

iex> Calendar.ISO.quarter_of_year(2016, 1, 31)
1
iex> Calendar.ISO.quarter_of_year(2016, 4, 3)
2
iex> Calendar.ISO.quarter_of_year(-99, 9, 31)
3
iex> Calendar.ISO.quarter_of_year(2018, 12, 28)
4

time_from_day_fraction(arg)

Specs

time_from_day_fraction(Calendar.day_fraction()) ::
  {hour(), minute(), second(), microsecond()}

Converts a day fraction to this Calendar's representation of time.

Examples

iex> Calendar.ISO.time_from_day_fraction({1, 2})
{12, 0, 0, {0, 6}}
iex> Calendar.ISO.time_from_day_fraction({13, 24})
{13, 0, 0, {0, 6}}

time_to_day_fraction(hour, minute, second, arg)

Specs

time_to_day_fraction(
  Calendar.hour(),
  Calendar.minute(),
  Calendar.second(),
  Calendar.microsecond()
) :: Calendar.day_fraction()

Returns the normalized day fraction of the specified time.

Examples

iex> Calendar.ISO.time_to_day_fraction(0, 0, 0, {0, 6})
{0, 86400000000}
iex> Calendar.ISO.time_to_day_fraction(12, 34, 56, {123, 6})
{45296000123, 86400000000}

time_to_string(hour, minute, second, microsecond, format \\ :extended)

Specs

time_to_string(
  Calendar.hour(),
  Calendar.minute(),
  Calendar.second(),
  Calendar.microsecond(),
  :basic | :extended
) :: String.t()

Converts the given time into a string.

By default, returns times formatted in the "extended" format, for human readability. It also supports the "basic" format by passing the :basic option.

Examples

iex> Calendar.ISO.time_to_string(2, 2, 2, {2, 6})
"02:02:02.000002"
iex> Calendar.ISO.time_to_string(2, 2, 2, {2, 2})
"02:02:02.00"
iex> Calendar.ISO.time_to_string(2, 2, 2, {2, 0})
"02:02:02"

iex> Calendar.ISO.time_to_string(2, 2, 2, {2, 6}, :basic)
"020202.000002"
iex> Calendar.ISO.time_to_string(2, 2, 2, {2, 6}, :extended)
"02:02:02.000002"

valid_date?(year, month, day)

Specs

valid_date?(year(), month(), day()) :: boolean()

Determines if the date given is valid according to the proleptic Gregorian calendar.

Examples

iex> Calendar.ISO.valid_date?(2015, 2, 28)
true
iex> Calendar.ISO.valid_date?(2015, 2, 30)
false
iex> Calendar.ISO.valid_date?(-1, 12, 31)
true
iex> Calendar.ISO.valid_date?(-1, 12, 32)
false

valid_time?(hour, minute, second, microsecond)

Specs

valid_time?(
  Calendar.hour(),
  Calendar.minute(),
  Calendar.second(),
  Calendar.microsecond()
) :: boolean()

Determines if the date given is valid according to the proleptic Gregorian calendar.

Note that while ISO 8601 allows times to specify 24:00:00 as the zero hour of the next day, this notation is not supported by Elixir. Leap seconds are not supported as well by the built-in Calendar.ISO.

Examples

iex> Calendar.ISO.valid_time?(10, 50, 25, {3006, 6})
true
iex> Calendar.ISO.valid_time?(23, 59, 60, {0, 0})
false
iex> Calendar.ISO.valid_time?(24, 0, 0, {0, 0})
false

year_of_era(year)

Specs

year_of_era(year()) :: {1..10000, era()}

Calculates the year and era from the given year.

The ISO calendar has two eras: the "current era" (CE) which starts in year 1 and is defined as era 1. And "before the current era" (BCE) for those years less than 1, defined as era 0.

Examples

iex> Calendar.ISO.year_of_era(1)
{1, 1}
iex> Calendar.ISO.year_of_era(2018)
{2018, 1}
iex> Calendar.ISO.year_of_era(0)
{1, 0}
iex> Calendar.ISO.year_of_era(-1)
{2, 0}