PySide6.QtCore.QDate¶
- class QDate¶
The
QDate
class provides date functions. More…Synopsis¶
Methods¶
def
__init__()
def
__reduce__()
def
__repr__()
def
addDays()
def
addMonths()
def
addYears()
def
day()
def
dayOfWeek()
def
dayOfYear()
def
daysInMonth()
def
daysInYear()
def
daysTo()
def
endOfDay()
def
getDate()
def
isNull()
def
isValid()
def
month()
def
__ne__()
def
__lt__()
def
__le__()
def
__eq__()
def
__gt__()
def
__ge__()
def
setDate()
def
startOfDay()
def
toJulianDay()
def
toPython()
def
toString()
def
weekNumber()
def
year()
Static functions¶
def
currentDate()
def
fromJulianDay()
def
fromString()
def
isLeapYear()
def
isValid()
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 aQCalendar
object.QDate
objects should be passed by value rather than by reference to const; they simply packageqint64
.A
QDate
object is typically created by giving the year, month, and day numbers explicitly. Note thatQDate
interprets year numbers less than 100 as presented, i.e., as years 1 through 99, without adding any offset. The static functioncurrentDate()
creates aQDate
object containing the date read from the system clock. An explicit date can also be set usingsetDate()
. ThefromString()
function returns aQDate
given a string and a date format which is used to interpret the date within the string.The
year()
,month()
, andday()
functions provide access to the year, month, and day numbers. When more than one of these values is needed, it is more efficient to callpartsFromDate()
, to save repeating (potentially expensive) calendrical calculations.Also,
dayOfWeek()
anddayOfYear()
functions are provided. The same information is provided in textual format bytoString()
.QLocale
can map the day numbers to names,QCalendar
can map month numbers to names.QDate
provides a full set of operators to compare twoQDate
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 useaddMonths()
andaddYears()
. ThedaysTo()
function returns the number of days between two dates.The
daysInMonth()
anddaysInYear()
functions return how many days there are in this date’s month and year, respectively. TheisLeapYear()
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; seehasYearZero()
.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 usingfromJulianDay()
.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 aQDateTime
can represent.- __init__()¶
Constructs a null date. Null dates are invalid.
- __init__(y, m, d)
- Parameters:
y – int
m – int
d – int
Constructs a date with year
y
, monthm
and dayd
.The date is understood in terms of the Gregorian calendar. If the specified date is invalid, the date is not set and
isValid()
returnsfalse
.- __init__(y, m, d, cal)
- Parameters:
y – int
m – int
d – int
cal –
QCalendar
- __reduce__()¶
- Return type:
str
- __repr__()¶
- Return type:
str
Returns a
QDate
object containing a datendays
later than the date of this object (or earlier ifndays
is negative).Returns a null date if the current date is invalid or the new date is out of range.
See also
This is an overloaded function.
Returns a
QDate
object containing a datenmonths
later than the date of this object (or earlier ifnmonths
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
This is an overloaded function.
Returns a
QDate
object containing a datenyears
later than the date of this object (or earlier ifnyears
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
Returns the system clock’s current date.
See also
- 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.See also
- 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.See also
- 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.See also
- 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.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 ifd
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
This is an overloaded function.
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() ofOffsetFromUTC
orUTC
, the time representation has no transitions so the end of the day isQTime
(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 byQDateTime
.See also
- endOfDay(spec[, offsetSeconds=0])
-
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.
Converts the Julian day
jd
to aQDate
.See also
- static fromString(string[, format=Qt.TextDate])¶
- Parameters:
string – str
format –
DateFormat
- Return type:
This is an overloaded function.
- static fromString(string[, format=Qt.TextDate])
- Parameters:
string – str
format –
DateFormat
- Return type:
Returns the
QDate
represented by thestring
, using theformat
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
- static fromString(string, format, cal)
This is an overloaded function.
- static fromString(string, format[, baseYear=QLocale.DefaultTwoDigitBaseYear])
- Parameters:
string – str
format – str
baseYear – int
- Return type:
This is an overloaded function.
Uses a default-constructed
QCalendar
.- static fromString(string, format, cal)
This is an overloaded function.
- static fromString(string, format[, baseYear=QLocale.DefaultTwoDigitBaseYear])
- Parameters:
string – str
format – str
baseYear – int
- Return type:
This is an overloaded function.
Uses a default-constructed
QCalendar
.- static fromString(string, format, cal)
This is an overloaded function.
- static fromString(string, format[, baseYear=QLocale.DefaultTwoDigitBaseYear])
- Parameters:
string – str
format – str
baseYear – int
- Return type:
This is an overloaded function.
Uses a default-constructed
QCalendar
.- static fromString(string, format, baseYear, cal)
This is an overloaded function.
- static fromString(string, format, baseYear, cal)
This is an overloaded function.
- static fromString(string, format, baseYear, cal)
Warning
This section contains snippets that were automatically translated from C++ to Python and may contain errors.
Returns the
QDate
represented by thestring
, using theformat
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 atbaseYear
are the candidates first considered. Prior to 6.7 there was nobaseYear
parameter and 1900 was always used. This is the default forbaseYear
, selecting a year from then to 1999. Passing 1976 asbaseYear
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 bybaseYear
, prefering later over earlier. SeematchCenturyToWeekday()
andDate 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.
See also
- 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
- static isLeapYear(year)¶
- Parameters:
year – int
- Return type:
bool
Returns
true
if the specifiedyear
is a leap year in the Gregorian calendar; otherwise returnsfalse
.See also
- isNull()¶
- Return type:
bool
Returns
true
if the date is null; otherwise returnsfalse
. A null date is invalid.- isValid()¶
- Return type:
bool
Returns
true
if this date is valid; otherwise returnsfalse
.See also
- 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
, andday
) is valid in the Gregorian calendar; otherwise returnsfalse
.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
- 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.
See also
Returns
true
iflhs
andrhs
represent distinct days; otherwise returnsfalse
.See also
operator==()
Returns
true
iflhs
is earlier thanrhs
; otherwise returnsfalse
.Returns
true
iflhs
is earlier than or equal torhs
; otherwise returnsfalse
.Returns
true
iflhs
andrhs
represent the same day, otherwisefalse
.Returns
true
iflhs
is later thanrhs
; otherwise returnsfalse
.Returns
true
iflhs
is later than or equal torhs
; otherwise returnsfalse
.- 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
andday
numbers. Returns true if the resulting date is valid, otherwise it sets this to represent an invalid date and returns false.See also
- 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 givenyear
,month
andday
numbers. Returns true if the resulting date is valid, otherwise it sets this to represent an invalid date and returns false.See also
This is an overloaded function.
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 isOffsetFromUTC
orUTC
, the time representation has no transitions so the start of the day isQTime
(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 byQDateTime
.See also
- startOfDay(spec[, offsetSeconds=0])
-
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
andoffsetSeconds
(ignored unlessspec
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
isOffsetFromUTC
,offsetSeconds
gives an implied zone’s offset from UTC. As UTC and such zones have no transitions, the start of the day isQTime
(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
asspec
(instead of passing aQTimeZone
) will also produce an invalid result, as shall dates that start outside the range representable byQDateTime
.- toJulianDay()¶
- Return type:
int
Converts the date to a Julian day.
See also
- 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
isTextDate
, 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, seetoString()
.If the
format
isISODate
, 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
isRFC2822Date
, 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.
- toString(format)
- Parameters:
format – str
- Return type:
str
This is an overloaded function.
- toString(format, cal)
- Parameters:
format – str
cal –
QCalendar
- Return type:
str
- toString(format, cal)
- Parameters:
format – str
cal –
QCalendar
- 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 notNone
(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
- 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.