Timex.Date
Module for working with dates.
Functions that produce time intervals use UNIX epoch (or simly Epoch) as the default reference date. Epoch is defined as UTC midnight of January 1, 1970.
Time intervals in this module don't account for leap seconds.
Supported tasks:
- get current date in the desired time zone
- convert dates between time zones and time units
- introspect dates to find out weekday, week number, number of days in a given month, etc.
- parse dates from string
- compare dates
- date arithmetic
Summary
Functions
Add time to a date using a timestamp, i.e. {megasecs, secs, microsecs} Same as shift(date, Time.to_timestamp(5, :mins), :timestamp)
Gets the current century
Given a date, get the century this date is in
Compare two dates returning one of the following values:
Returns the ordinal day number of the date
Get the name of the day corresponding to the provided number
Get the short name of the day corresponding to the provided number
Get the day of the week corresponding to the given name
Return the number of days in the month which the date falls on
Calculate time interval between two dates. If the second date comes after the first one in time, return value will be positive; and negative otherwise. You must specify one of the following units:
The date of Epoch, used as default reference date by this module and also by the Time module
Time interval since year 0 of Epoch expressed in the specified units
Determine if two dates represent the same point in time
Construct a date from Erlang's date or datetime value
Construct a date from a time interval since Epoch or year 0
Convert an iso ordinal day number to the day it represents in the current year. If no date is provided, a new one will be created, with the time will be set to 0:00:00, in UTC. Otherwise, the date provided will have it's month and day reset to the date represented by the ordinal day
Given an ISO triplet {year, week number, weekday}
, convert it to a DateTime struct
Return a boolean indicating whether the given year is a leap year. You may pase a date or a year number
Return a boolean indicating whether the given date is valid
Return a 3-tuple {year, week number, weekday} for the given date
Return a pair {year, week number} (as defined by ISO 8601) that date falls on
Get current local date
Convert a date to your local timezone
Get the name of the month corresponding to the provided number
Get the short name of the month corresponding to the provided number
Get the number of the month corresponding to the given name
Produce a valid date from a possibly invalid one
Get current date
Get representation of the current date in seconds or days since Epoch
Return a new date with the specified fields replaced by new values
A single function for adjusting the date using various units: timestamp, seconds, minutes, hours, days, weeks, months, years
Subtract time from a date using a timestamp, i.e. {megasecs, secs, microsecs} Same as shift(date, Time.to_timestamp(5, :mins) |> Time.invert, :timestamp)
Get a TimezoneInfo object for the specified offset or name
Convert the date to an integer number of days since Epoch or year 0
Convert a date to an integer number of seconds since Epoch or year 0. With to_secs/3
, you can also specify an option utc: false | true
, which controls whether the DateTime is converted to UTC prior to calculating the number of seconds from the reference date. By default, UTC conversion is enabled
Convert a date to a timestamp value consumable by the Time module
Get current the current datetime in UTC
Convert a date to UTC
Return weekday number (as defined by ISO 8601) of the specified date
The first day of year zero (calendar module's default reference date)
Types
day :: 1 .. 31
daynum :: 1 .. 366
dtz :: {datetime, Timex.TimezoneInfo.t}
hour :: 0 .. 23
iso_triplet :: {year, weeknum, weekday}
megaseconds :: non_neg_integer
microseconds :: non_neg_integer
minute :: 0 .. 59
month :: 1 .. 12
num_of_days :: 28 .. 31
second :: 0 .. 59
seconds :: non_neg_integer
timestamp :: {megaseconds, seconds, microseconds}
weekday :: 1 .. 7
weeknum :: 1 .. 53
year :: non_neg_integer
Functions
Specs
add(Timex.DateTime.t, timestamp) :: Timex.DateTime.t
Add time to a date using a timestamp, i.e. {megasecs, secs, microsecs} Same as shift(date, Time.to_timestamp(5, :mins), :timestamp).
Specs
century :: non_neg_integer
Gets the current century
Examples
iex> Elixir.Timex.Date.century
21
Specs
century(Timex.DateTime.t) :: non_neg_integer
Given a date, get the century this date is in.
Examples
iex> Elixir.Timex.Date.now |> Elixir.Timex.Date.century
21
Specs
compare(Timex.DateTime.t, Timex.DateTime.t | :epoch | :zero | :distant_past | :distant_future) ::
-1 |
0 |
1
Compare two dates returning one of the following values:
-1
-- the first date comes before the second one0
-- both arguments represent the same date when coalesced to the same timezone.1
-- the first date comes after the second one
You can optionality specify a granularity of any of
:years :months :weeks :days :hours :mins :secs :timestamp
and the dates will be compared with the cooresponding accuracy. The default granularity is :secs.
Examples
iex> date1 = Elixir.Timex.Date.from({2014, 3, 4})
iex> date2 = Elixir.Timex.Date.from({2015, 3, 4})
iex> Elixir.Timex.Date.compare(date1, date2, :years)
-1
iex> Elixir.Timex.Date.compare(date2, date1, :years)
1
iex> Elixir.Timex.Date.compare(date1, date1)
0
Specs
compare(Timex.DateTime.t, Timex.DateTime.t, :years | :months | :weeks | :days | :hours | :mins | :secs | :timestamp) ::
-1 |
0 |
1
Specs
day(Timex.DateTime.t) :: daynum
Returns the ordinal day number of the date.
Examples
iex> Elixir.Timex.Date.from({{2015,6,26},{0,0,0}}) |> Elixir.Timex.Date.day
177
Specs
day_name(weekday) :: binary
Get the name of the day corresponding to the provided number
Examples
iex> Elixir.Timex.Date.day_name(1)
"Monday"
iex> Elixir.Timex.Date.day_name(0)
{:error, "Invalid day num: 0"}
Specs
day_shortname(weekday) :: binary
Get the short name of the day corresponding to the provided number
Examples
iex> Elixir.Timex.Date.day_shortname(1)
"Mon"
iex> Elixir.Timex.Date.day_shortname(0)
{:error, "Invalid day num: 0"}
Specs
day_to_num(binary | atom) :: integer
Get the day of the week corresponding to the given name.
Examples
iex> Elixir.Timex.Date.day_to_num("Monday")
1
iex> Elixir.Timex.Date.day_to_num("monday")
1
iex> Elixir.Timex.Date.day_to_num("Mon")
1
iex> Elixir.Timex.Date.day_to_num("mon")
1
iex> Elixir.Timex.Date.day_to_num(:mon)
1
Specs
days_in_month(Timex.DateTime.t | {year, month}) :: num_of_days
Return the number of days in the month which the date falls on.
Examples
iex> Elixir.Timex.Date.epoch |> Elixir.Timex.Date.days_in_month
31
Specs
diff(Timex.DateTime.t, Timex.DateTime.t, :secs | :mins | :hours | :days | :weeks | :months | :years) :: integer
diff(Timex.DateTime.t, Timex.DateTime.t, :timestamp) :: timestamp
Calculate time interval between two dates. If the second date comes after the first one in time, return value will be positive; and negative otherwise. You must specify one of the following units:
:years :months :weeks :days :hours :mins :secs :timestamp
and the result will be an integer value of those units or a timestamp.
Specs
epoch :: Timex.DateTime.t
The date of Epoch, used as default reference date by this module and also by the Time module.
See also zero/0
.
Examples
iex> date = %Timex.DateTime{year: 1970, month: 1, day: 1, timezone: %Timex.TimezoneInfo{}}
iex> Elixir.Timex.Date.epoch === date
true
Specs
epoch(:secs | :days) :: integer
epoch(:timestamp) :: timestamp
Time interval since year 0 of Epoch expressed in the specified units.
Examples
iex> Elixir.Timex.Date.epoch(:timestamp)
{0,0,0}
iex> Elixir.Timex.Date.epoch(:secs)
62167219200
Specs
equal?(Timex.DateTime.t, Timex.DateTime.t) :: boolean
Determine if two dates represent the same point in time
Examples
iex> date1 = Elixir.Timex.Date.from({2014, 3, 1})
iex> date2 = Elixir.Timex.Date.from({2014, 3, 1})
iex> Elixir.Timex.Date.equal?(date1, date2)
true
Specs
from(datetime | date) :: Timex.DateTime.t
Construct a date from Erlang's date or datetime value.
You may specify the date's time zone as the second argument. If the argument is omitted, UTC time zone is assumed.
When passing {year, month, day} as the first argument, the resulting date will indicate midnight of that day in the specified timezone (UTC by default).
NOTE: When using from
the input value is normalized to prevent invalid dates from being accidentally introduced. Use set
with validate: false
, or create the %DateTime{} by hand if you do not want normalization. ## Examples
> Date.from(:erlang.universaltime) #=> %DateTime{...}
> Date.from(:erlang.localtime) #=> %Datetime{...}
> Date.from(:erlang.localtime, :local) #=> %DateTime{...}
> Date.from({2014,3,16}, "America/Chicago") #=> %DateTime{...}
Specs
from(number, :us | :secs | :days) :: Timex.DateTime.t
from(timestamp, :timestamp) :: Timex.DateTime.t
from(datetime | date, :utc | :local | Timex.TimezoneInfo.t | binary) :: Timex.DateTime.t
Specs
from(number, :us | :secs | :days, :epoch | :zero) :: Timex.DateTime.t
from(timestamp, :timestamp, :epoch | :zero) :: Timex.DateTime.t
Construct a date from a time interval since Epoch or year 0.
UTC time zone is assumed. This assumption can be modified by setting desired time zone using set/3 after the date is constructed.
Examples
> Date.from(13, :secs)
> Date.from(13, :days, :zero)
> Date.from(Time.now, :timestamp)
Specs
from_iso_day(non_neg_integer, Timex.DateTime.t | nil) :: Timex.DateTime.t
Convert an iso ordinal day number to the day it represents in the current year. If no date is provided, a new one will be created, with the time will be set to 0:00:00, in UTC. Otherwise, the date provided will have it's month and day reset to the date represented by the ordinal day.
Examples
# Creating a DateTime from the given day
iex> expected = Elixir.Timex.Date.from({{2015, 6, 29}, {0,0,0}})
iex> (Elixir.Timex.Date.from_iso_day(180) === expected)
true
# Shifting a DateTime to the given day
iex> date = Elixir.Timex.Date.from({{2015,6,26}, {12,0,0}})
iex> expected = Elixir.Timex.Date.from({{2015, 6, 29}, {12,0,0}})
iex> (Elixir.Timex.Date.from_iso_day(180, date) === expected)
true
Specs
from_iso_triplet(iso_triplet) :: Timex.DateTime.t
Given an ISO triplet {year, week number, weekday}
, convert it to a DateTime struct.
Examples
iex> expected = Elixir.Timex.Date.from({2014, 1, 28})
iex> Elixir.Timex.Date.from_iso_triplet({2014, 5, 2}) === expected
true
Specs
is_leap?(Timex.DateTime.t | year) :: boolean
Return a boolean indicating whether the given year is a leap year. You may pase a date or a year number.
Examples
iex> Elixir.Timex.Date.epoch |> Elixir.Timex.Date.is_leap?
false
iex> Elixir.Timex.Date.is_leap?(2012)
true
Specs
is_valid?(dtz | Timex.DateTime.t) :: boolean
Return a boolean indicating whether the given date is valid.
Examples
iex> Elixir.Timex.Date.from({{1,1,1}, {1,1,1}}) |> Elixir.Timex.Date.is_valid?
true
iex> %Timex.DateTime{} |> Elixir.Timex.Date.set([month: 13, validate: false]) |> Elixir.Timex.Date.is_valid?
false
iex> %Timex.DateTime{} |> Elixir.Timex.Date.set(hour: -1) |> Elixir.Timex.Date.is_valid?
false
Specs
iso_triplet(Timex.DateTime.t) :: {year, weeknum, weekday}
Return a 3-tuple {year, week number, weekday} for the given date.
Examples
iex> Elixir.Timex.Date.epoch |> Elixir.Timex.Date.iso_triplet
{1970, 1, 4}
Specs
iso_week(Timex.DateTime.t) :: {year, weeknum}
Return a pair {year, week number} (as defined by ISO 8601) that date falls on.
Examples
iex> Elixir.Timex.Date.epoch |> Elixir.Timex.Date.iso_week
{1970,1}
Specs
local :: Timex.DateTime.t
Get current local date.
See also universal/0
.
Examples
> Elixir.Timex.Date.local
%Timex.DateTime{year: 2013, month: 3, day: 16, hour: 11, minute: 1, second: 12, timezone: %TimezoneInfo{}}
Specs
local(date :: Timex.DateTime.t) :: Timex.DateTime.t
Convert a date to your local timezone.
See also universal/1
.
Examples
Date.now |> Date.local
Specs
month_name(month) :: binary
Get the name of the month corresponding to the provided number
Examples
iex> Elixir.Timex.Date.month_name(1)
"January"
iex> Elixir.Timex.Date.month_name(0)
{:error, "Invalid month num: 0"}
Specs
month_shortname(month) :: binary
Get the short name of the month corresponding to the provided number
Examples
iex> Elixir.Timex.Date.month_name(1)
"January"
iex> Elixir.Timex.Date.month_name(0)
{:error, "Invalid month num: 0"}
Specs
month_to_num(binary) :: integer
Get the number of the month corresponding to the given name.
Examples
iex> Elixir.Timex.Date.month_to_num("January")
1
iex> Elixir.Timex.Date.month_to_num("january")
1
iex> Elixir.Timex.Date.month_to_num("Jan")
1
iex> Elixir.Timex.Date.month_to_num("jan")
1
iex> Elixir.Timex.Date.month_to_num(:jan)
1
Specs
normalize(datetime | dtz | {date, time, Timex.TimezoneInfo.t}) :: Timex.DateTime.t
Produce a valid date from a possibly invalid one.
All date's components will be clamped to the minimum or maximum valid value.
Examples
iex> expected = Elixir.Timex.Date.from({{1, 12, 31}, {0, 59, 59}}, :local)
iex> date = {{1,12,31},{0,59,59}}
iex> localtz = Timex.Timezone.local(date)
iex> result = {{1,12,31},{0,59,59}, localtz} |> Elixir.Timex.Date.normalize |> Elixir.Timex.Date.local
iex> result === expected
true
Specs
now :: Timex.DateTime.t
Get current date.
Examples
> Elixir.Timex.Date.now
%Timex.DateTime{year: 2015, month: 6, day: 26, hour: 23, minute: 56, second: 12}
Specs
now(:secs | :days) :: integer
now(binary) :: Timex.DateTime.t
Get representation of the current date in seconds or days since Epoch.
See convert/2 for converting arbitrary dates to various time units.
Examples
> Elixir.Timex.Date.now(:secs)
1363439013
> Elixir.Timex.Date.now(:days)
15780
Specs
set(Timex.DateTime.t, [{atom, term}]) :: Timex.DateTime.t
Return a new date with the specified fields replaced by new values.
Values are automatically validated and clamped to good values by default. If you wish to skip validation, perhaps for performance reasons, pass validate: false
.
Values are applied in order, so if you pass [datetime: dt, date: d]
, the date value from date
will override datetime
's date value.
Examples
iex> now = Elixir.Timex.Date.epoch
iex> Elixir.Timex.Date.set(now, date: {1,1,1})
%Timex.DateTime{year: 1, month: 1, day: 1, hour: 0, minute: 0, second: 0, timezone: %Timex.TimezoneInfo{}, calendar: :gregorian}
iex> Elixir.Timex.Date.set(now, hour: 8)
%Timex.DateTime{year: 1970, month: 1, day: 1, hour: 8, minute: 0, second: 0, timezone: %Timex.TimezoneInfo{}, calendar: :gregorian}
iex> Elixir.Timex.Date.set(now, [date: {2013,3,26}, hour: 30])
%Timex.DateTime{year: 2013, month: 3, day: 26, hour: 23, minute: 0, second: 0, timezone: %Timex.TimezoneInfo{}, calendar: :gregorian}
iex> Elixir.Timex.Date.set(now, [
...> datetime: {{2013,3,26}, {12,30,0}},
...> date: {2014,4,12}
...>])
%Timex.DateTime{year: 2014, month: 4, day: 12, hour: 12, minute: 30, second: 0, timezone: %Timex.TimezoneInfo{}, calendar: :gregorian}
iex> Elixir.Timex.Date.set(now, [minute: 74, validate: false])
%Timex.DateTime{year: 1970, month: 1, day: 1, hour: 0, minute: 74, second: 0, timezone: %Timex.TimezoneInfo{}, calendar: :gregorian}
Specs
shift(Timex.DateTime.t, [{atom, term}]) :: Timex.DateTime.t
A single function for adjusting the date using various units: timestamp, seconds, minutes, hours, days, weeks, months, years.
When shifting by timestamps, microseconds are ignored.
If the list contains :month
and at least one other unit, an ArgumentError is raised (due to ambiguity of such shifts). You can still shift by months separately.
If :year
is present, it is applied in the last turn.
The returned date is always valid. If after adding months or years the day exceeds maximum number of days in the resulting month, that month's last day is used.
To prevent day skew, fix up the date after shifting. For example, if you want to land on the last day of the next month, do the following:
shift(date, 1, :month) |> set(:month, 31)
Since set/3
is capping values that are out of range, you will get the correct last day for each month.
Examples
date = from({{2013,3,5}, {23,23,23}})
local(shift(date, secs: 24*3600*365))
#=> {{2014,3,5}, {23,23,23}}
local(shift(date, secs: -24*3600*(365*2 + 1))) # +1 day for leap year 2012
#=> {{2011,3,5}, {23,23,23}}
local(shift(date, [secs: 13, day: -1, week: 2]))
#=> {{2013,3,18}, {23,23,36}}
Specs
subtract(Timex.DateTime.t, timestamp) :: Timex.DateTime.t
Subtract time from a date using a timestamp, i.e. {megasecs, secs, microsecs} Same as shift(date, Time.to_timestamp(5, :mins) |> Time.invert, :timestamp).
Specs
timezone(:local | :utc | number | binary, Timex.DateTime.t | nil) :: Timex.TimezoneInfo.t
Get a TimezoneInfo object for the specified offset or name.
When offset or name is invalid, exception is raised.
Examples
iex> date = Elixir.Timex.Date.from({2015, 4, 12})
iex> tz = Elixir.Timex.Date.timezone(:utc, date)
iex> tz.full_name
"UTC"
iex> date = Elixir.Timex.Date.from({2015, 4, 12})
iex> tz = Elixir.Timex.Date.timezone("America/Chicago", date)
iex> {tz.full_name, tz.abbreviation}
{"America/Chicago", "CDT"}
iex> date = Elixir.Timex.Date.from({2015, 4, 12})
iex> tz = Elixir.Timex.Date.timezone(+2, date)
iex> {tz.full_name, tz.abbreviation}
{"Etc/GMT-2", "GMT-2"}
Specs
to_days(Timex.DateTime.t, :epoch | :zero) :: integer
Convert the date to an integer number of days since Epoch or year 0.
See also diff/2
if you want to specify an arbitray reference date.
Examples
iex> Elixir.Timex.Date.from({1970, 1, 15}) |> Elixir.Timex.Date.to_days
14
Specs
to_secs(Timex.DateTime.t, :epoch | :zero, [{:utc, false | true}]) :: integer
Convert a date to an integer number of seconds since Epoch or year 0. With to_secs/3
, you can also specify an option utc: false | true
, which controls whether the DateTime is converted to UTC prior to calculating the number of seconds from the reference date. By default, UTC conversion is enabled.
See also diff/2
if you want to specify an arbitrary reference date.
Examples
iex> Elixir.Timex.Date.from({{1999, 1, 2}, {12,13,14}}) |> Elixir.Timex.Date.to_secs
915279194
Specs
to_timestamp(Timex.DateTime.t, :epoch | :zero) :: timestamp
Convert a date to a timestamp value consumable by the Time module.
See also diff/2
if you want to specify an arbitrary reference date.
Examples
iex> Elixir.Timex.Date.epoch |> Elixir.Timex.Date.to_timestamp
{0,0,0}
Specs
universal :: Timex.DateTime.t
Get current the current datetime in UTC.
See also local/0
. Delegates to now/0
, since they are identical in behavior
Examples
> Elixir.Timex.Date.universal
%Timex.DateTime{timezone: %Timex.TimezoneInfo{full_name: "UTC"}}
Specs
universal(Timex.DateTime.t) :: Timex.DateTime.t
Convert a date to UTC
See also local/1
.
Examples
> localdate = Date.local
%Timex.DateTime{hour: 5, timezone: %Timex.TimezoneInfo{full_name: "America/Chicago"}}
> localdate |> Date.universal
%Timex.DateTime{hour: 10, timezone: %Timex.TimezoneInfo{full_name: "UTC"}}
Specs
weekday(Timex.DateTime.t) :: weekday
Return weekday number (as defined by ISO 8601) of the specified date.
Examples
iex> Elixir.Timex.Date.epoch |> Elixir.Timex.Date.weekday
4 # (i.e. Thursday)
Specs
zero :: Timex.DateTime.t
The first day of year zero (calendar module's default reference date).
See also epoch/0
.
Examples
iex> date = %Timex.DateTime{year: 0, month: 1, day: 1, timezone: %Timex.TimezoneInfo{}}
iex> Elixir.Timex.Date.zero === date
true