class QDate

The QDate class provides date functions. More…

Synopsis

Methods

Static functions

Note

This documentation may contain snippets that were automatically translated from C++ to Python. We always welcome contributions to the snippet translation. If you see an issue with the translation, you can also let us know by creating a ticket on https:/bugreports.qt.io/projects/PYSIDE

Detailed Description

A QDate object represents a particular day, regardless of calendar, locale or other settings used when creating it or supplied by the system. It can report the year, month and day of the month that represent the day with respect to the proleptic Gregorian calendar or any calendar supplied as a QCalendar object. QDate objects should be passed by value rather than by reference to const; they simply package qint64.

A QDate object is typically created by giving the year, month, and day numbers explicitly. Note that QDate interprets year numbers less than 100 as presented, i.e., as years 1 through 99, without adding any offset. The static function currentDate() creates a QDate object containing the date read from the system clock. An explicit date can also be set using setDate() . The fromString() function returns a QDate given a string and a date format which is used to interpret the date within the string.

The year() , month() , and day() functions provide access to the year, month, and day numbers. When more than one of these values is needed, it is more efficient to call partsFromDate() , to save repeating (potentially expensive) calendrical calculations.

Also, dayOfWeek() and dayOfYear() functions are provided. The same information is provided in textual format by toString() . QLocale can map the day numbers to names, QCalendar can map month numbers to names.

QDate provides a full set of operators to compare two QDate objects where smaller means earlier, and larger means later.

You can increment (or decrement) a date by a given number of days using addDays() . Similarly you can use addMonths() and addYears() . The daysTo() function returns the number of days between two dates.

The daysInMonth() and daysInYear() functions return how many days there are in this date’s month and year, respectively. The isLeapYear() function indicates whether a date is in a leap year. QCalendar can also supply this information, in some cases more conveniently.

Remarks

Note

All conversion to and from string formats is done using the C locale. For localized conversions, see QLocale .

In the Gregorian calendar, there is no year 0. Dates in that year are considered invalid. The year -1 is the year “1 before Christ” or “1 before common era.” The day before 1 January 1 CE, QDate (1, 1, 1), is 31 December 1 BCE, QDate (-1, 12, 31). Various other calendars behave similarly; see hasYearZero() .

Range of Valid Dates

Dates are stored internally as a Julian Day number, an integer count of every day in a contiguous range, with 24 November 4714 BCE in the Gregorian calendar being Julian Day 0 (1 January 4713 BCE in the Julian calendar). As well as being an efficient and accurate way of storing an absolute date, it is suitable for converting a date into other calendar systems such as Hebrew, Islamic or Chinese. The Julian Day number can be obtained using toJulianDay() and can be set using fromJulianDay() .

The range of Julian Day numbers that QDate can represent is, for technical reasons, limited to between -784350574879 and 784354017364, which means from before 2 billion BCE to after 2 billion CE. This is more than seven times as wide as the range of dates a QDateTime can represent.

See also

QTime QDateTime QCalendar YearRange QDateEditQDateTimeEditQCalendarWidget

__init__()

Constructs a null date. Null dates are invalid.

See also

isNull() isValid()

__init__(y, m, d)
Parameters:

  • y – int

  • m – int

  • d – int

Constructs a date with year y, month m and day d.

The date is understood in terms of the Gregorian calendar. If the specified date is invalid, the date is not set and isValid() returns false.

Warning

Years 1 to 99 are interpreted as is. Year 0 is invalid.

See also

isValid() dateFromParts()

__init__(y, m, d, cal)
Parameters:

  • y – int

  • m – int

  • d – int

  • cal – QCalendar

__reduce__()
Return type:

str

__repr__()
Return type:

str

addDays(days)
Parameters:

days – int

Return type:

QDate

Returns a QDate object containing a date ndays later than the date of this object (or earlier if ndays is negative).

Returns a null date if the current date is invalid or the new date is out of range.

addMonths(months)
Parameters:

months – int

Return type:

QDate

This is an overloaded function.

addMonths(months, cal)
Parameters:
Return type:

QDate

Returns a QDate object containing a date nmonths later than the date of this object (or earlier if nmonths is negative).

Uses cal as calendar, if supplied, else the Gregorian calendar.

Note

If the ending day/month combination does not exist in the resulting month/year, this function will return a date that is the latest valid date in the selected month.

See also

addDays() addYears()

addYears(years)
Parameters:

years – int

Return type:

QDate

This is an overloaded function.

addYears(years, cal)
Parameters:
Return type:

QDate

Returns a QDate object containing a date nyears later than the date of this object (or earlier if nyears is negative).

Uses cal as calendar, if supplied, else the Gregorian calendar.

Note

If the ending day/month combination does not exist in the resulting year (e.g., for the Gregorian calendar, if the date was Feb 29 and the final year is not a leap year), this function will return a date that is the latest valid date in the given month (in the example, Feb 28).

See also

addDays() addMonths()

static currentDate()
Return type:

QDate

Returns the system clock’s current date.

day()
Return type:

int

This is an overloaded function.

day(cal)
Parameters:

cal – QCalendar

Return type:

int

Returns the day of the month for this date.

Uses cal as calendar if supplied, else the Gregorian calendar (for which the return ranges from 1 to 31). Returns 0 if the date is invalid.

dayOfWeek()
Return type:

int

This is an overloaded function.

dayOfWeek(cal)
Parameters:

cal – QCalendar

Return type:

int

Returns the weekday (1 = Monday to 7 = Sunday) for this date.

Uses cal as calendar if supplied, else the Gregorian calendar. Returns 0 if the date is invalid. Some calendars may give special meaning (e.g. intercallary days) to values greater than 7.

dayOfYear()
Return type:

int

This is an overloaded function.

dayOfYear(cal)
Parameters:

cal – QCalendar

Return type:

int

Returns the day of the year (1 for the first day) for this date.

Uses cal as calendar if supplied, else the Gregorian calendar. Returns 0 if either the date or the first day of its year is invalid.

daysInMonth()
Return type:

int

This is an overloaded function.

daysInMonth(cal)
Parameters:

cal – QCalendar

Return type:

int

Returns the number of days in the month for this date.

Uses cal as calendar if supplied, else the Gregorian calendar (for which the result ranges from 28 to 31). Returns 0 if the date is invalid.

daysInYear()
Return type:

int

This is an overloaded function.

daysInYear(cal)
Parameters:

cal – QCalendar

Return type:

int

Returns the number of days in the year for this date.

Uses cal as calendar if supplied, else the Gregorian calendar (for which the result is 365 or 366). Returns 0 if the date is invalid.

daysTo(d)
Parameters:

d – QDate

Return type:

int

Warning

This section contains snippets that were automatically translated from C++ to Python and may contain errors.

Returns the number of days from this date to d (which is negative if d is earlier than this date).

Returns 0 if either date is invalid.

Example:

QDate d1(1995, 5, 17) # May 17, 1995
QDate d2(1995, 5, 20) # May 20, 1995
d1.daysTo(d2) # returns 3
d2.daysTo(d1) # returns -3

See also

addDays()

endOfDay()
Return type:

QDateTime

This is an overloaded function.

endOfDay(zone)
Parameters:

zone – QTimeZone

Return type:

QDateTime

Returns the end-moment of the day.

When a day ends depends on a how time is described: each day starts and ends earlier for those in time-zones further west and later for those in time-zones further east. The time representation to use can be specified by an optional time zone. The default time representation is the system’s local time.

Usually, the end of the day is one millisecond before the midnight, 24:00: however, if a time-zone transition causes the given date to skip over that moment (e.g. a DST spring-forward skipping over 23:00 and the following hour), the actual latest time in the day is returned. This can only arise when the time representation is a time-zone or local time.

When zone has a timeSpec() of OffsetFromUTC or UTC , the time representation has no transitions so the end of the day is QTime (23, 59, 59, 999).

In the rare case of a date that was entirely skipped (this happens when a zone east of the international date-line switches to being west of it), the return shall be invalid. Passing an invalid time-zone as zone will also produce an invalid result, as shall dates that end outside the range representable by QDateTime .

See also

startOfDay()

endOfDay(spec[, offsetSeconds=0])
Parameters:

  • spec – TimeSpec

  • offsetSeconds – int

Return type:

QDateTime

Note

This function is deprecated.

This is an overloaded function.

Use endOfDay(const QTimeZone &) instead. Returns the end-moment of the day. When a day ends depends on a how time is described: each day starts and ends earlier for those with higher offsets from UTC and later for those with lower offsets from UTC. The time representation to use can be specified either by a \a spec and \a offsetSeconds (ignored unless \a spec is Qt::OffsetSeconds) or by a time zone. Usually, the end of the day is one millisecond before the midnight, 24:00: however, if a local time transition causes the given date to skip over that moment (e.g. a DST spring-forward skipping over 23:00 and the following hour), the actual latest time in the day is returned. When \a spec is Qt::OffsetFromUTC, \a offsetSeconds gives the implied zone's offset from UTC. As UTC and such zones have no transitions, the end of the day is QTime(23, 59, 59, 999) in these cases. In the rare case of a date that was entirely skipped (this happens when a zone east of the international date-line switches to being west of it), the return shall be invalid. Passing Qt::TimeZone as \a spec (instead of passing a QTimeZone) will also produce an invalid result, as shall dates that end outside the range representable by QDateTime.

static fromJulianDay(jd_)
Parameters:

jd – int

Return type:

QDate

Converts the Julian day jd to a QDate .

See also

toJulianDay()

static fromString(string[, format=Qt.TextDate])
Parameters:
Return type:

QDate

This is an overloaded function.

static fromString(string[, format=Qt.TextDate])
Parameters:
Return type:

QDate

Returns the QDate represented by the string, using the format given, or an invalid date if the string cannot be parsed.

Note for TextDate : only English month names (e.g. “Jan” in short form or “January” in long form) are recognized.

See also

toString() toDate()

static fromString(string, format, cal)
Parameters:

  • string – str

  • format – str

  • cal – QCalendar

Return type:

QDate

This is an overloaded function.

static fromString(string, format[, baseYear=QLocale.DefaultTwoDigitBaseYear])
Parameters:

  • string – str

  • format – str

  • baseYear – int

Return type:

QDate

This is an overloaded function.

Uses a default-constructed QCalendar .

static fromString(string, format, cal)
Parameters:

  • string – str

  • format – str

  • cal – QCalendar

Return type:

QDate

This is an overloaded function.

static fromString(string, format[, baseYear=QLocale.DefaultTwoDigitBaseYear])
Parameters:

  • string – str

  • format – str

  • baseYear – int

Return type:

QDate

This is an overloaded function.

Uses a default-constructed QCalendar .

static fromString(string, format, cal)
Parameters:

  • string – str

  • format – str

  • cal – QCalendar

Return type:

QDate

This is an overloaded function.

static fromString(string, format[, baseYear=QLocale.DefaultTwoDigitBaseYear])
Parameters:

  • string – str

  • format – str

  • baseYear – int

Return type:

QDate

This is an overloaded function.

Uses a default-constructed QCalendar .

static fromString(string, format, baseYear, cal)
Parameters:

  • string – str

  • format – str

  • baseYear – int

  • cal – QCalendar

Return type:

QDate

This is an overloaded function.

static fromString(string, format, baseYear, cal)
Parameters:

  • string – str

  • format – str

  • baseYear – int

  • cal – QCalendar

Return type:

QDate

This is an overloaded function.

static fromString(string, format, baseYear, cal)
Parameters:

  • string – str

  • format – str

  • baseYear – int

  • cal – QCalendar

Return type:

QDate

Warning

This section contains snippets that were automatically translated from C++ to Python and may contain errors.

Returns the QDate represented by the string, using the format given, or an invalid date if the string cannot be parsed.

Uses cal as calendar if supplied, else the Gregorian calendar. Ranges of values in the format descriptions below are for the latter; they may be different for other calendars.

These expressions may be used for the format:

Expression

Output

d

The day as a number without a leading zero (1 to 31)

dd

The day as a number with a leading zero (01 to 31)

ddd

The abbreviated day name (‘Mon’ to ‘Sun’).

dddd

The long day name (‘Monday’ to ‘Sunday’).

M

The month as a number without a leading zero (1 to 12)

MM

The month as a number with a leading zero (01 to 12)

MMM

The abbreviated month name (‘Jan’ to ‘Dec’).

MMMM

The long month name (‘January’ to ‘December’).

yy

The year as a two digit number (00 to 99)

yyyy

The year as a four digit number, possibly plus a leading minus sign for negative years.

Note

Day and month names must be given in English (C locale). If localized month and day names are to be recognized, use system() .toDate().

All other input characters will be treated as text. Any non-empty sequence of characters enclosed in single quotes will also be treated (stripped of the quotes) as text and not be interpreted as expressions. For example:

date = QDate.fromString("1MM12car2003", "d'MM'MMcaryyyy")
# date is 1 December 2003

If the format is not satisfied, an invalid QDate is returned. The expressions that don’t expect leading zeroes (d, M) will be greedy. This means that they will use two digits even if this will put them outside the accepted range of values and leaves too few digits for other sections. For example, the following format string could have meant January 30 but the M will grab two digits, resulting in an invalid date:

date = QDate.fromString("130", "Md") # invalid()

For any field that is not represented in the format the following defaults are used:

Field

Default value

Year

baseYear (or 1900)

Month

1 (January)

Day

1

When format only specifies the last two digits of a year, the 100 years starting at baseYear are the candidates first considered. Prior to 6.7 there was no baseYear parameter and 1900 was always used. This is the default for baseYear, selecting a year from then to 1999. Passing 1976 as baseYear will select a year from 1976 through 2075, for example. When the format also includes month, day (of month) and day-of-week, these suffice to imply the century. In such a case, a matching date is selected in the nearest century to the one indicated by baseYear, prefering later over earlier. See matchCenturyToWeekday() and Date ambiguities for further details,

The following examples demonstrate the default values:

QDate.fromString("1.30", "M.d") # January 30 1900
QDate.fromString("20000110", "yyyyMMdd") # January 10, 2000
QDate.fromString("20000110", "yyyyMd") # January 10, 2000

Note

If a format character is repeated more times than the longest expression in the table above using it, this part of the format will be read as several expressions with no separator between them; the longest above, possibly repeated as many times as there are copies of it, ending with a residue that may be a shorter expression. Thus 'MMMMMMMMMM' would match "MayMay05" and set the month to May. Likewise, 'MMMMMM' would match "May08" and find it inconsistent, leading to an invalid date.

Date ambiguities

Different cultures use different formats for dates and, as a result, users may mix up the order in which date fields should be given. For example, "Wed 28-Nov-01" might mean either 2028 November 1st or the 28th of November, 2001 (each of which happens to be a Wednesday). Using format "ddd yy-MMM-dd" it shall be interpreted the first way, using "ddd dd-MMM-yy" the second. However, which the user meant may depend on the way the user normally writes dates, rather than the format the code was expecting.

The example considered above mixed up day of the month and a two-digit year. Similar confusion can arise over interchanging the month and day of the month, when both are given as numbers. In these cases, including a day of the week field in the date format can provide some redundancy, that may help to catch errors of this kind. However, as in the example above, this is not always effective: the interchange of two fields (or their meanings) may produce dates with the same day of the week.

Including a day of the week in the format can also resolve the century of a date specified using only the last two digits of its year. Unfortunately, when combined with a date in which the user (or other source of data) has mixed up two of the fields, this resolution can lead to finding a date which does match the format’s reading but isn’t the one intended by its author. Likewise, if the user simply gets the day of the week wrong, in an otherwise correct date, this can lead a date in a different century. In each case, finding a date in a different century can turn a wrongly-input date into a wildly different one.

The best way to avoid date ambiguities is to use four-digit years and months specified by name (whether full or abbreviated), ideally collected via user interface idioms that make abundantly clear to the user which part of the date they are selecting. Including a day of the week can also help by providing the means to check consistency of the data. Where data comes from the user, using a format supplied by a locale selected by the user, it is best to use a long format as short formats are more likely to use two-digit years. Of course, it is not always possible to control the format - data may come from a source you do not control, for example.

As a result of these possible sources of confusion, particularly when you cannot be sure an unambiguous format is in use, it is important to check that the result of reading a string as a date is not just valid but reasonable for the purpose for which it was supplied. If the result is outside some range of reasonable values, it may be worth getting the user to confirm their date selection, showing the date read from the string in a long format that does include month name and four-digit year, to make it easier for them to recognize any errors.

getDate()
Return type:

(year, month, day)

Extracts the date’s year, month, and day, and assigns them to *``year``, *``month``, and *``day``. The pointers may be null.

Returns 0 if the date is invalid.

Note

In Qt versions prior to 5.7, this function is marked as non-const.

See also

year() month() day() isValid() partsFromDate()

static isLeapYear(year)
Parameters:

year – int

Return type:

bool

Returns true if the specified year is a leap year in the Gregorian calendar; otherwise returns false.

See also

isLeapYear()

isNull()
Return type:

bool

Returns true if the date is null; otherwise returns false. A null date is invalid.

Note

The behavior of this function is equivalent to isValid() .

See also

isValid()

isValid()
Return type:

bool

Returns true if this date is valid; otherwise returns false.

static isValid(y, m, d)
Parameters:

  • y – int

  • m – int

  • d – int

Return type:

bool

Warning

This section contains snippets that were automatically translated from C++ to Python and may contain errors.

This is an overloaded function.

Returns true if the specified date (year, month, and day) is valid in the Gregorian calendar; otherwise returns false.

Example:

QDate.isValid(2002, 5, 17) # true
QDate.isValid(2002, 2, 30) # false (Feb 30 does not exist)
QDate.isValid(2004, 2, 29) # true (2004 is a leap year)
QDate.isValid(2000, 2, 29) # true (2000 is a leap year)
QDate.isValid(2006, 2, 29) # false (2006 is not a leap year)
QDate.isValid(2100, 2, 29) # false (2100 is not a leap year)
QDate.isValid(1202, 6, 6) # true (even though 1202 is pre-Gregorian)

See also

isNull() setDate() isDateValid()

month()
Return type:

int

This is an overloaded function.

month(cal)
Parameters:

cal – QCalendar

Return type:

int

Returns the month-number for the date.

Numbers the months of the year starting with 1 for the first. Uses cal as calendar if supplied, else the Gregorian calendar, for which the month numbering is as follows:

  • 1 = “January”

  • 2 = “February”

  • 3 = “March”

  • 4 = “April”

  • 5 = “May”

  • 6 = “June”

  • 7 = “July”

  • 8 = “August”

  • 9 = “September”

  • 10 = “October”

  • 11 = “November”

  • 12 = “December”

Returns 0 if the date is invalid. Note that some calendars may have more than 12 months in some years.

__ne__(rhs)
Parameters:

rhs – QDate

Return type:

bool

Returns true if lhs and rhs represent distinct days; otherwise returns false.

See also

operator==()

__lt__(rhs)
Parameters:

rhs – QDate

Return type:

bool

Returns true if lhs is earlier than rhs; otherwise returns false.

__le__(rhs)
Parameters:

rhs – QDate

Return type:

bool

Returns true if lhs is earlier than or equal to rhs; otherwise returns false.

__eq__(rhs)
Parameters:

rhs – QDate

Return type:

bool

Returns true if lhs and rhs represent the same day, otherwise false.

__gt__(rhs)
Parameters:

rhs – QDate

Return type:

bool

Returns true if lhs is later than rhs; otherwise returns false.

__ge__(rhs)
Parameters:

rhs – QDate

Return type:

bool

Returns true if lhs is later than or equal to rhs; otherwise returns false.

setDate(year, month, day)
Parameters:

  • year – int

  • month – int

  • day – int

Return type:

bool

Sets this to represent the date, in the Gregorian calendar, with the given year, month and day numbers. Returns true if the resulting date is valid, otherwise it sets this to represent an invalid date and returns false.

setDate(year, month, day, cal)
Parameters:

  • year – int

  • month – int

  • day – int

  • cal – QCalendar

Return type:

bool

Sets this to represent the date, in the given calendar cal, with the given year, month and day numbers. Returns true if the resulting date is valid, otherwise it sets this to represent an invalid date and returns false.

startOfDay()
Return type:

QDateTime

This is an overloaded function.

startOfDay(zone)
Parameters:

zone – QTimeZone

Return type:

QDateTime

Returns the start-moment of the day.

When a day starts depends on a how time is described: each day starts and ends earlier for those in time-zones further west and later for those in time-zones further east. The time representation to use can be specified by an optional time zone. The default time representation is the system’s local time.

Usually, the start of the day is midnight, 00:00: however, if a time-zone transition causes the given date to skip over that midnight (e.g. a DST spring-forward skipping over the first hour of the day day), the actual earliest time in the day is returned. This can only arise when the time representation is a time-zone or local time.

When zone has a timeSpec() of is OffsetFromUTC or UTC , the time representation has no transitions so the start of the day is QTime (0, 0).

In the rare case of a date that was entirely skipped (this happens when a zone east of the international date-line switches to being west of it), the return shall be invalid. Passing an invalid time-zone as zone will also produce an invalid result, as shall dates that start outside the range representable by QDateTime .

See also

endOfDay()

startOfDay(spec[, offsetSeconds=0])
Parameters:

  • spec – TimeSpec

  • offsetSeconds – int

Return type:

QDateTime

Note

This function is deprecated.

This is an overloaded function.

Use startOfDay(const QTimeZone &) instead.

Returns the start-moment of the day.

When a day starts depends on a how time is described: each day starts and ends earlier for those with higher offsets from UTC and later for those with lower offsets from UTC. The time representation to use can be specified either by a spec and offsetSeconds (ignored unless spec is Qt::OffsetSeconds) or by a time zone.

Usually, the start of the day is midnight, 00:00: however, if a local time transition causes the given date to skip over that midnight (e.g. a DST spring-forward skipping over the first hour of the day day), the actual earliest time in the day is returned.

When spec is OffsetFromUTC , offsetSeconds gives an implied zone’s offset from UTC. As UTC and such zones have no transitions, the start of the day is QTime (0, 0) in these cases.

In the rare case of a date that was entirely skipped (this happens when a zone east of the international date-line switches to being west of it), the return shall be invalid. Passing TimeZone as spec (instead of passing a QTimeZone ) will also produce an invalid result, as shall dates that start outside the range representable by QDateTime .

toJulianDay()
Return type:

int

Converts the date to a Julian day.

See also

fromJulianDay()

toPython()
Return type:

object

toString(format)
Parameters:

format – str

Return type:

str

This is an overloaded function.

toString([format=Qt.TextDate])
Parameters:

format – DateFormat

Return type:

str

This is an overloaded function.

Returns the date as a string. The format parameter determines the format of the string.

If the format is TextDate , the string is formatted in the default way. The day and month names will be in English. An example of this formatting is “Sat May 20 1995”. For localized formatting, see toString() .

If the format is ISODate , the string format corresponds to the ISO 8601 extended specification for representations of dates and times, taking the form yyyy-MM-dd, where yyyy is the year, MM is the month of the year (between 01 and 12), and dd is the day of the month between 01 and 31.

If the format is RFC2822Date , the string is formatted in an RFC 2822 compatible way. An example of this formatting is “20 May 1995”.

If the date is invalid, an empty string will be returned.

Warning

The ISODate format is only valid for years in the range 0 to 9999.

See also

fromString() toString()

toString(format)
Parameters:

format – str

Return type:

str

This is an overloaded function.

toString(format, cal)
Parameters:
Return type:

str

toString(format, cal)
Parameters:
Return type:

str

weekNumber()
Return type:

(week, yearNumber)

Returns the ISO 8601 week number (1 to 53).

Returns 0 if the date is invalid. Otherwise, returns the week number for the date. If yearNumber is not None (its default), stores the year as *``yearNumber``.

In accordance with ISO 8601, each week falls in the year to which most of its days belong, in the Gregorian calendar. As ISO 8601’s week starts on Monday, this is the year in which the week’s Thursday falls. Most years have 52 weeks, but some have 53.

Note

*``yearNumber`` is not always the same as year() . For example, 1 January 2000 has week number 52 in the year 1999, and 31 December 2002 has week number 1 in the year 2003.

See also

isValid()

year()
Return type:

int

This is an overloaded function.

year(cal)
Parameters:

cal – QCalendar

Return type:

int

Returns the year of this date.

Uses cal as calendar, if supplied, else the Gregorian calendar.

Returns 0 if the date is invalid. For some calendars, dates before their first year may all be invalid.

If using a calendar which has a year 0, check using isValid() if the return is 0. Such calendars use negative year numbers in the obvious way, with year 1 preceded by year 0, in turn preceded by year -1 and so on.

Some calendars, despite having no year 0, have a conventional numbering of the years before their first year, counting backwards from 1. For example, in the proleptic Gregorian calendar, successive years before 1 CE (the first year) are identified as 1 BCE, 2 BCE, 3 BCE and so on. For such calendars, negative year numbers are used to indicate these years before year 1, with -1 indicating the year before 1.