Dates and Time

Period
Year
Month
Week
Day
Hour
Minute
Second
Millisecond
Microsecond
Nanosecond

Period types represent discrete, human representations of time.

CompoundPeriod

A CompoundPeriod is useful for expressing time periods that are not a fixed multiple of smaller periods. For example, "a year and a day" is not a fixed number of days, but can be expressed using a CompoundPeriod. In fact, a CompoundPeriod is automatically generated by addition of different period types, e.g. Year(1) + Day(1) produces a CompoundPeriod result.

Instant

Instant types represent integer-based, machine representations of time as continuous timelines starting from an epoch.

UTInstant{T}

The UTInstant represents a machine timeline based on UT time (1 day = one revolution of the earth). The T is a Period parameter that indicates the resolution or precision of the instant.

TimeType

TimeType types wrap Instant machine instances to provide human representations of the machine instant. Time, DateTime and Date are subtypes of TimeType.

DateTime

DateTime wraps a UTInstant{Millisecond} and interprets it according to the proleptic Gregorian calendar.

Date

Date wraps a UTInstant{Day} and interprets it according to the proleptic Gregorian calendar.

Time

Time wraps a Nanosecond and represents a specific moment in a 24-hour day.

DateTime(y, [m, d, h, mi, s, ms]) -> DateTime

Construct a DateTime type by parts. Arguments must be convertible to Int64.

DateTime(periods::Period...) -> DateTime

Construct a DateTime type by Period type parts. Arguments may be in any order. DateTime parts not provided will default to the value of Dates.default(period).

DateTime(f::Function, y[, m, d, h, mi, s]; step=Day(1), limit=10000) -> DateTime

Create a DateTime through the adjuster API. The starting point will be constructed from the provided y, m, d... arguments, and will be adjusted until f::Function returns true. The step size in adjusting can be provided manually through the step keyword. limit provides a limit to the max number of iterations the adjustment API will pursue before throwing an error (in the case that f::Function is never satisfied).

DateTime(dt::Date) -> DateTime

Converts a Date to a DateTime. The hour, minute, second, and millisecond parts of the new DateTime are assumed to be zero.

DateTime(dt::AbstractString, format::AbstractString; locale="english") -> DateTime

Construct a DateTime by parsing the dt date string following the pattern given in the format string.

This method creates a DateFormat object each time it is called. If you are parsing many date strings of the same format, consider creating a DateFormat object once and using that as the second argument instead.

format(dt::TimeType, format::AbstractString; locale="english") -> AbstractString

Construct a string by using a TimeType object and applying the provided format. The following character codes can be used to construct the format string:

The number of sequential code characters indicate the width of the code. A format of yyyy-mm specifies that the code y should have a width of four while m a width of two. Codes that yield numeric digits have an associated mode: fixed-width or minimum-width. The fixed-width mode left-pads the value with zeros when it is shorter than the specified width and truncates the value when longer. Minimum-width mode works the same as fixed-width except that it does not truncate values longer than the width.

When creating a format you can use any non-code characters as a separator. For example to generate the string "1996-01-15T00:00:00" you could use format: "yyyy-mm-ddTHH:MM:SS". Note that if you need to use a code character as a literal you can use the escape character backslash. The string "1996y01m" can be produced with the format "yyyy\ymm\m".

DateFormat(format::AbstractString, locale="english") -> DateFormat

Construct a date formatting object that can be used for parsing date strings or formatting a date object as a string. The following character codes can be used to construct the format string:

Characters not listed above are normally treated as delimiters between date and time slots. For example a dt string of "1996-01-15T00:00:00.0" would have a format string like "y-m-dTH:M:S.s". If you need to use a code character as a delimiter you can escape it using backslash. The date "1995y01m" would have the format "y\ym\m".

Creating a DateFormat object is expensive. Whenever possible, create it once and use it many times or try the dateformat"" string macro. Using this macro creates the DateFormat object once at macro expansion time and reuses it later. see @dateformat_str.

See DateTime and format for how to use a DateFormat object to parse and write Date strings respectively.

dateformat"Y-m-d H:M:S"

Create a DateFormat object. Similar to DateFormat("Y-m-d H:M:S") but creates the DateFormat object once during macro expansion.

See DateFormat for details about format specifiers.

DateTime(dt::AbstractString, df::DateFormat) -> DateTime

Construct a DateTime by parsing the dt date string following the pattern given in the DateFormat object. Similar to DateTime(::AbstractString, ::AbstractString) but more efficient when repeatedly parsing similarly formatted date strings with a pre-created DateFormat object.

Date(y, [m, d]) -> Date

Construct a Date type by parts. Arguments must be convertible to Int64.

Date(period::Period...) -> Date

Construct a Date type by Period type parts. Arguments may be in any order. Date parts not provided will default to the value of Dates.default(period).

Date(f::Function, y[, m, d]; step=Day(1), limit=10000) -> Date

Create a Date through the adjuster API. The starting point will be constructed from the provided y, m, d arguments, and will be adjusted until f::Function returns true. The step size in adjusting can be provided manually through the step keyword. limit provides a limit to the max number of iterations the adjustment API will pursue before throwing an error (given that f::Function is never satisfied).

Date(dt::DateTime) -> Date

Converts a DateTime to a Date. The hour, minute, second, and millisecond parts of the DateTime are truncated, so only the year, month and day parts are used in construction.

Date(dt::AbstractString, format::AbstractString; locale="english") -> Date

Construct a Date object by parsing a dt date string following the pattern given in the format string. Follows the same conventions as DateTime(::AbstractString, ::AbstractString).

Date(dt::AbstractString, df::DateFormat) -> Date

Parse a date from a date string dt using a DateFormat object df.

Time(h, [mi, s, ms, us, ns]) -> Time

Construct a Time type by parts. Arguments must be convertible to Int64.

Time(period::TimePeriod...) -> Time

Construct a Time type by Period type parts. Arguments may be in any order. Time parts not provided will default to the value of Dates.default(period).

Time(f::Function, h, mi=0; step::Period=Second(1), limit::Int=10000)
Time(f::Function, h, mi, s; step::Period=Millisecond(1), limit::Int=10000)
Time(f::Function, h, mi, s, ms; step::Period=Microsecond(1), limit::Int=10000)
Time(f::Function, h, mi, s, ms, us; step::Period=Nanosecond(1), limit::Int=10000)

Create a Time through the adjuster API. The starting point will be constructed from the provided h, mi, s, ms, us arguments, and will be adjusted until f::Function returns true. The step size in adjusting can be provided manually through the step keyword. limit provides a limit to the max number of iterations the adjustment API will pursue before throwing an error (in the case that f::Function is never satisfied). Note that the default step will adjust to allow for greater precision for the given arguments; i.e. if hour, minute, and second arguments are provided, the default step will be Millisecond(1) instead of Second(1).

Time(dt::DateTime) -> Time

Converts a DateTime to a Time. The hour, minute, second, and millisecond parts of the DateTime are used to create the new Time. Microsecond and nanoseconds are zero by default.

now() -> DateTime

Returns a DateTime corresponding to the user's system time including the system timezone locale.

now(::Type{UTC}) -> DateTime

Returns a DateTime corresponding to the user's system time as UTC/GMT.

eps(::DateTime) -> Millisecond
eps(::Date) -> Day
eps(::Time) -> Nanosecond

Returns Millisecond(1) for DateTime values, Day(1) for Date values, and Nanosecond(1) for Time values.

year(dt::TimeType) -> Int64

The year of a Date or DateTime as an Int64.

month(dt::TimeType) -> Int64

The month of a Date or DateTime as an Int64.

week(dt::TimeType) -> Int64

Return the ISO week date of a Date or DateTime as an Int64. Note that the first week of a year is the week that contains the first Thursday of the year which can result in dates prior to January 4th being in the last week of the previous year. For example week(Date(2005,1,1)) is the 53rd week of 2004.

day(dt::TimeType) -> Int64

The day of month of a Date or DateTime as an Int64.

hour(dt::DateTime) -> Int64

The hour of day of a DateTime as an Int64.

hour(t::Time) -> Int64

The hour of a Time as an Int64.

minute(dt::DateTime) -> Int64

The minute of a DateTime as an Int64.

minute(t::Time) -> Int64

The minute of a Time as an Int64.

second(dt::DateTime) -> Int64

The second of a DateTime as an Int64.

second(t::Time) -> Int64

The second of a Time as an Int64.

millisecond(dt::DateTime) -> Int64

The millisecond of a DateTime as an Int64.

millisecond(t::Time) -> Int64

The millisecond of a Time as an Int64.

microsecond(t::Time) -> Int64

The microsecond of a Time as an Int64.

nanosecond(t::Time) -> Int64

The nanosecond of a Time as an Int64.

Year(v)

Construct a Year object with the given v value. Input must be losslessly convertible to an Int64.

Month(v)

Construct a Month object with the given v value. Input must be losslessly convertible to an Int64.

Week(v)

Construct a Week object with the given v value. Input must be losslessly convertible to an Int64.

Day(v)

Construct a Day object with the given v value. Input must be losslessly convertible to an Int64.

Hour(dt::DateTime) -> Hour

The hour part of a DateTime as a Hour.

Minute(dt::DateTime) -> Minute

The minute part of a DateTime as a Minute.

Second(dt::DateTime) -> Second

The second part of a DateTime as a Second.

Millisecond(dt::DateTime) -> Millisecond

The millisecond part of a DateTime as a Millisecond.

Microsecond(dt::Time) -> Microsecond

The microsecond part of a Time as a Microsecond.

Nanosecond(dt::Time) -> Nanosecond

The nanosecond part of a Time as a Nanosecond.

yearmonth(dt::TimeType) -> (Int64, Int64)

Simultaneously return the year and month parts of a Date or DateTime.

monthday(dt::TimeType) -> (Int64, Int64)

Simultaneously return the month and day parts of a Date or DateTime.

yearmonthday(dt::TimeType) -> (Int64, Int64, Int64)

Simultaneously return the year, month and day parts of a Date or DateTime.

dayname(dt::TimeType; locale="english") -> AbstractString

Return the full day name corresponding to the day of the week of the Date or DateTime in the given locale.

dayabbr(dt::TimeType; locale="english") -> AbstractString

Return the abbreviated name corresponding to the day of the week of the Date or DateTime in the given locale.

dayofweek(dt::TimeType) -> Int64

Returns the day of the week as an Int64 with 1 = Monday, 2 = Tuesday, etc..

dayofmonth(dt::TimeType) -> Int64

The day of month of a Date or DateTime as an Int64.

dayofweekofmonth(dt::TimeType) -> Int

For the day of week of dt, returns which number it is in dt's month. So if the day of the week of dt is Monday, then 1 = First Monday of the month, 2 = Second Monday of the month, etc. In the range 1:5.

daysofweekinmonth(dt::TimeType) -> Int

For the day of week of dt, returns the total number of that day of the week in dt's month. Returns 4 or 5. Useful in temporal expressions for specifying the last day of a week in a month by including dayofweekofmonth(dt) == daysofweekinmonth(dt) in the adjuster function.

monthname(dt::TimeType; locale="english") -> AbstractString

Return the full name of the month of the Date or DateTime in the given locale.

monthabbr(dt::TimeType; locale="english") -> AbstractString

Return the abbreviated month name of the Date or DateTime in the given locale.

daysinmonth(dt::TimeType) -> Int

Returns the number of days in the month of dt. Value will be 28, 29, 30, or 31.

isleapyear(dt::TimeType) -> Bool

Returns true if the year of dt is a leap year.

dayofyear(dt::TimeType) -> Int

Returns the day of the year for dt with January 1st being day 1.

daysinyear(dt::TimeType) -> Int

Returns 366 if the year of dt is a leap year, otherwise returns 365.

quarterofyear(dt::TimeType) -> Int

Returns the quarter that dt resides in. Range of value is 1:4.

dayofquarter(dt::TimeType) -> Int

Returns the day of the current quarter of dt. Range of value is 1:92.

trunc(dt::TimeType, ::Type{Period}) -> TimeType

Truncates the value of dt according to the provided Period type. E.g. if dt is 1996-01-01T12:30:00, then trunc(dt,Day) == 1996-01-01T00:00:00.

firstdayofweek(dt::TimeType) -> TimeType

Adjusts dt to the Monday of its week.

lastdayofweek(dt::TimeType) -> TimeType

Adjusts dt to the Sunday of its week.

firstdayofmonth(dt::TimeType) -> TimeType

Adjusts dt to the first day of its month.

lastdayofmonth(dt::TimeType) -> TimeType

Adjusts dt to the last day of its month.

firstdayofyear(dt::TimeType) -> TimeType

Adjusts dt to the first day of its year.

lastdayofyear(dt::TimeType) -> TimeType

Adjusts dt to the last day of its year.

firstdayofquarter(dt::TimeType) -> TimeType

Adjusts dt to the first day of its quarter.

lastdayofquarter(dt::TimeType) -> TimeType

Adjusts dt to the last day of its quarter.

tonext(dt::TimeType, dow::Int; same::Bool=false) -> TimeType

Adjusts dt to the next day of week corresponding to dow with 1 = Monday, 2 = Tuesday, etc. Setting same=true allows the current dt to be considered as the next dow, allowing for no adjustment to occur.

toprev(dt::TimeType, dow::Int; same::Bool=false) -> TimeType

Adjusts dt to the previous day of week corresponding to dow with 1 = Monday, 2 = Tuesday, etc. Setting same=true allows the current dt to be considered as the previous dow, allowing for no adjustment to occur.

tofirst(dt::TimeType, dow::Int; of=Month) -> TimeType

Adjusts dt to the first dow of its month. Alternatively, of=Year will adjust to the first dow of the year.

tolast(dt::TimeType, dow::Int; of=Month) -> TimeType

Adjusts dt to the last dow of its month. Alternatively, of=Year will adjust to the last dow of the year.

tonext(func::Function, dt::TimeType; step=Day(1), limit=10000, same=false) -> TimeType

Adjusts dt by iterating at most limit iterations by step increments until func returns true. func must take a single TimeType argument and return a Bool. same allows dt to be considered in satisfying func.

toprev(func::Function, dt::TimeType; step=Day(-1), limit=10000, same=false) -> TimeType

Adjusts dt by iterating at most limit iterations by step increments until func returns true. func must take a single TimeType argument and return a Bool. same allows dt to be considered in satisfying func.

Year(v)
Month(v)
Week(v)
Day(v)
Hour(v)
Minute(v)
Second(v)
Millisecond(v)
Microsecond(v)
Nanosecond(v)

Construct a Period type with the given v value. Input must be losslessly convertible to an Int64.

CompoundPeriod(periods) -> CompoundPeriod

Construct a CompoundPeriod from a Vector of Periods. All Periods of the same type will be added together.

Examples

julia> Dates.CompoundPeriod(Dates.Hour(12), Dates.Hour(13))
25 hours

julia> Dates.CompoundPeriod(Dates.Hour(-1), Dates.Minute(1))
-1 hour, 1 minute

julia> Dates.CompoundPeriod(Dates.Month(1), Dates.Week(-2))
1 month, -2 weeks

julia> Dates.CompoundPeriod(Dates.Minute(50000))
50000 minutes

default(p::Period) -> Period

Returns a sensible "default" value for the input Period by returning T(1) for Year, Month, and Day, and T(0) for Hour, Minute, Second, and Millisecond.

floor(dt::TimeType, p::Period) -> TimeType

Returns the nearest Date or DateTime less than or equal to dt at resolution p.

For convenience, p may be a type instead of a value: floor(dt, Dates.Hour) is a shortcut for floor(dt, Dates.Hour(1)).

julia> floor(Date(1985, 8, 16), Dates.Month)
1985-08-01

julia> floor(DateTime(2013, 2, 13, 0, 31, 20), Dates.Minute(15))
2013-02-13T00:30:00

julia> floor(DateTime(2016, 8, 6, 12, 0, 0), Dates.Day)
2016-08-06T00:00:00

ceil(dt::TimeType, p::Period) -> TimeType

Returns the nearest Date or DateTime greater than or equal to dt at resolution p.

For convenience, p may be a type instead of a value: ceil(dt, Dates.Hour) is a shortcut for ceil(dt, Dates.Hour(1)).

julia> ceil(Date(1985, 8, 16), Dates.Month)
1985-09-01

julia> ceil(DateTime(2013, 2, 13, 0, 31, 20), Dates.Minute(15))
2013-02-13T00:45:00

julia> ceil(DateTime(2016, 8, 6, 12, 0, 0), Dates.Day)
2016-08-07T00:00:00

round(dt::TimeType, p::Period, [r::RoundingMode]) -> TimeType

Returns the Date or DateTime nearest to dt at resolution p. By default (RoundNearestTiesUp), ties (e.g., rounding 9:30 to the nearest hour) will be rounded up.

For convenience, p may be a type instead of a value: round(dt, Dates.Hour) is a shortcut for round(dt, Dates.Hour(1)).

julia> round(Date(1985, 8, 16), Dates.Month)
1985-08-01

julia> round(DateTime(2013, 2, 13, 0, 31, 20), Dates.Minute(15))
2013-02-13T00:30:00

julia> round(DateTime(2016, 8, 6, 12, 0, 0), Dates.Day)
2016-08-07T00:00:00

Valid rounding modes for round(::TimeType, ::Period, ::RoundingMode) are RoundNearestTiesUp (default), RoundDown (floor), and RoundUp (ceil).

floorceil(dt::TimeType, p::Period) -> (TimeType, TimeType)

Simultaneously return the floor and ceil of a Date or DateTime at resolution p. More efficient than calling both floor and ceil individually.

epochdays2date(days) -> Date

Takes the number of days since the rounding epoch (0000-01-01T00:00:00) and returns the corresponding Date.

epochms2datetime(milliseconds) -> DateTime

Takes the number of milliseconds since the rounding epoch (0000-01-01T00:00:00) and returns the corresponding DateTime.

date2epochdays(dt::Date) -> Int64

Takes the given Date and returns the number of days since the rounding epoch (0000-01-01T00:00:00) as an Int64.

datetime2epochms(dt::DateTime) -> Int64

Takes the given DateTime and returns the number of milliseconds since the rounding epoch (0000-01-01T00:00:00) as an Int64.

today() -> Date

Returns the date portion of now().

unix2datetime(x) -> DateTime

Takes the number of seconds since unix epoch 1970-01-01T00:00:00 and converts to the corresponding DateTime.

datetime2unix(dt::DateTime) -> Float64

Takes the given DateTime and returns the number of seconds since the unix epoch 1970-01-01T00:00:00 as a Float64.

julian2datetime(julian_days) -> DateTime

Takes the number of Julian calendar days since epoch -4713-11-24T12:00:00 and returns the corresponding DateTime.

datetime2julian(dt::DateTime) -> Float64

Takes the given DateTime and returns the number of Julian calendar days since the julian epoch -4713-11-24T12:00:00 as a Float64.

rata2datetime(days) -> DateTime

Takes the number of Rata Die days since epoch 0000-12-31T00:00:00 and returns the corresponding DateTime.

datetime2rata(dt::TimeType) -> Int64

Returns the number of Rata Die days since epoch from the given Date or DateTime.