- class QDateTime#
The
QDateTime
class provides date and time functions. More…Synopsis#
Methods#
def
__init__()
def
__reduce__()
def
__repr__()
def
addDays()
def
addMSecs()
def
addMonths()
def
addSecs()
def
addYears()
def
date()
def
daysTo()
def
isDaylightTime()
def
isNull()
def
isValid()
def
msecsTo()
def
offsetFromUtc()
def
__ne__()
def
__lt__()
def
__le__()
def
__eq__()
def
__gt__()
def
__ge__()
def
secsTo()
def
setDate()
def
setTime()
def
setTimeSpec()
def
setTimeZone()
def
swap()
def
time()
def
timeSpec()
def
timeZone()
def
toLocalTime()
def
toPython()
def
toString()
def
toTimeSpec()
def
toTimeZone()
def
toUTC()
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
QDateTime
object encodes a calendar date and a clock time (a “datetime”) in accordance with a time representation. It combines features of theQDate
andQTime
classes. It can read the current datetime from the system clock. It provides functions for comparing datetimes and for manipulating a datetime by adding a number of seconds, days, months, or years.QDateTime
can describe datetimes with respect tolocal time
, toUTC
, to a specifiedoffset from UTC
or to a specifiedtime zone
. Each of these time representations can be encapsulated in a suitable instance of theQTimeZone
class. For example, a time zone of “Europe/Berlin” will apply the daylight-saving rules as used in Germany. In contrast, a fixed offset from UTC of +3600 seconds is one hour ahead of UTC (usually written in ISO standard notation as “UTC+01:00”), with no daylight-saving complications. When using either local time or a specified time zone, time-zone transitions (seebelow
) are taken into account. AQDateTime
‘stimeSpec()
will tell you which of the four types of time representation is in use; itstimeRepresentation()
provides a full description of that time representation, as aQTimeZone
.A
QDateTime
object is typically created either by giving a date and time explicitly in the constructor, or by using a static function such ascurrentDateTime()
or fromMSecsSinceEpoch(). The date and time can be changed withsetDate()
andsetTime()
. A datetime can also be set using thesetMSecsSinceEpoch()
function that takes the time, in milliseconds, since the start, in UTC, of the year 1970. ThefromString()
function returns aQDateTime
, given a string and a date format used to interpret the date within the string.currentDateTime()
returns aQDateTime
that expresses the current date and time with respect to a specific time representation, such as local time (its default).currentDateTimeUtc()
returns aQDateTime
that expresses the current date and time with respect to UTC; it is equivalent toQDateTime::currentDateTime(QTimeZone::UTC)
.The
date()
andtime()
functions provide access to the date and time parts of the datetime. The same information is provided in textual format by thetoString()
function.QDateTime
provides a full set of operators to compare twoQDateTime
objects, where smaller means earlier and larger means later.You can increment (or decrement) a datetime by a given number of milliseconds using
addMSecs()
, seconds usingaddSecs()
, or days usingaddDays()
. Similarly, you can useaddMonths()
andaddYears()
. ThedaysTo()
function returns the number of days between two datetimes,secsTo()
returns the number of seconds between two datetimes, andmsecsTo()
returns the number of milliseconds between two datetimes. These operations are aware of daylight-saving time (DST) and other time-zone transitions, where applicable.Use
toTimeZone()
to re-express a datetime in terms of a different time representation. By passing a lightweightQTimeZone
that represents local time, UTC or a fixed offset from UTC, you can convert the datetime to use the corresponding time representation; or you can pass a full time zone (whosetimeSpec()
isQt::TimeZone
) to use that instead.Remarks#
Note
QDateTime
does not account for leap seconds.Note
All conversion to and from string formats is done using the C locale. For localized conversions, see
QLocale
.Note
There is no year 0 in the Gregorian calendar. 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 is 31 December 1 BCE.
Note
Using local time (the default) or a specified time zone implies a need to resolve any issues around
transitions
. As a result, operations on suchQDateTime
instances (notably including constructing them) may be more expensive than the equivalent when using UTC or a fixed offset from it.Range of Valid Dates#
The range of values that
QDateTime
can represent is dependent on the internal storage implementation.QDateTime
is currently stored in a qint64 as a serial msecs value encoding the date and time. This restricts the date range to about ±292 million years, compared to theQDate
range of ±2 billion years. Care must be taken when creating aQDateTime
with extreme values that you do not overflow the storage. The exact range of supported values varies depending on the time representation used.Use of Timezones#
QDateTime
uses the system’s time zone information to determine the current local time zone and its offset from UTC. If the system is not configured correctly or not up-to-date,QDateTime
will give wrong results.QDateTime
likewise uses system-provided information to determine the offsets of other timezones from UTC. If this information is incomplete or out of date,QDateTime
will give wrong results. See theQTimeZone
documentation for more details.On modern Unix systems, this means
QDateTime
usually has accurate information about historical transitions (including DST, see below) whenever possible. On Windows, where the system doesn’t support historical timezone data, historical accuracy is not maintained with respect to timezone transitions, notably including DST. However, building Qt with the ICU library will equipQTimeZone
with the same timezone database as is used on Unix.Timezone transitions#
QDateTime
takes into account timezone transitions, both the transitions between Standard Time and Daylight-Saving Time (DST) and the transitions that arise when a zone changes its standard offset. For example, if the transition is at 2am and the clock goes forward to 3am, then there is a “missing” hour from 02:00:00 to 02:59:59.999. Such a transition is known as a “spring forward” and the times skipped over have no meaning. When a transition goes the other way, known as a “fall back”, a time interval is repeated, first in the old zone (usually DST), then in the new zone (usually Standard Time), so times in this interval are ambiguous.Some zones use “reversed” DST, using standard time in summer and daylight-saving time (with a lowered offset) in winter. For such zones, the spring forward still happens in spring and skips an hour, but is a transition out of daylight-saving time, while the fall back still repeats an autumn hour but is a transition to daylight-saving time.
When converting from a UTC time (or a time at fixed offset from UTC), there is always an unambiguous valid result in any timezone. However, when combining a date and time to make a datetime, expressed with respect to local time or a specific time-zone, the nominal result may fall in a transition, making it either invalid or ambiguous. Methods where this situation may arise take a
resolve
parameter: this is always ignored if the requested datetime is valid and unambiguous. SeeTransitionResolution
for the options it lets you control. Prior to Qt 6.7, the equivalent of itsLegacyBehavior
was selected.For a spring forward’s skipped interval, interpreting the requested time with either offset yields an actual time at which the other offset was in use; so passing
TransitionResolution::RelativeToBefore
forresolve
will actually result in a time after the transition, that would have had the requested representation had the transition not happened. Likewise,TransitionResolution::RelativeToAfter
forresolve
results in a time before the transition, that would have had the requested representation, had the transition happened earlier.When
QDateTime
performs arithmetic, as with addDay() oraddSecs()
, it takes care to produce a valid result. For example, on a day when there is a spring forward from 02:00 to 03:00, adding one second to 01:59:59 will get 03:00:00. Adding one day to 02:30 on the preceding day will get 03:30 on the day of the transition, while subtracting one day, by callingaddDay(-1)
, to 02:30 on the following day will get 01:30 on the day of the transition. WhileaddSecs()
will deliver a time offset by the given number of seconds,addDays()
adjusts the date and only adjusts time if it would otherwise get an invalid result. ApplyingaddDays(1)
to 03:00 on the day before the spring-forward will simply get 03:00 on the day of the transition, even though the latter is only 23 hours after the former; butaddSecs(24 * 60 * 60)
will get 04:00 on the day of the transition, since that’s 24 hours later. Typical transitions make some days 23 or 25 hours long.For datetimes that the system
time_t
can represent (from 1901-12-14 to 2038-01-18 on systems with 32-bittime_t
; for the full rangeQDateTime
can represent if the type is 64-bit), the standard system APIs are used to determine local time’s offset from UTC. For datetimes not handled by these system APIs (potentially including some within thetime_t
range),systemTimeZone()
is used, if available, or a best effort is made to estimate. In any case, the offset information used depends on the system and may be incomplete or, for past times, historically inaccurate. Furthermore, for future dates, the local time zone’s offsets and DST rules may change before that date comes around.Whole day transitions#
A small number of zones have skipped or repeated entire days as part of moving The International Date Line across themselves. For these,
daysTo()
will be unaware of the duplication or gap, simply using the difference in calendar date; in contrast,msecsTo()
andsecsTo()
know the true time interval. Likewise,addMSecs()
andaddSecs()
correspond directly to elapsed time, whereaddDays()
,addMonths()
andaddYears()
follow the nominal calendar, aside from where landing in a gap or duplication requires resolving an ambiguity or invalidity due to a duplication or omission.Note
Days “lost” during a change of calendar, such as from Julian to Gregorian, do not affect
QDateTime
. Although the two calendars describe dates differently, the successive days across the change are described by consecutiveQDate
instances, each one day later than the previous, as described by either calendar or by their toJulianDay() values. In contrast, a zone skipping or duplicating a day is changing its description of time, not date, for all that it does so by a whole 24 hours.Offsets From UTC#
Offsets from UTC are measured in seconds east of Greenwich. The moment described by a particular date and time, such as noon on a particular day, depends on the time representation used. Those with a higher offset from UTC describe an earlier moment, and those with a lower offset a later moment, by any given combination of date and time.
There is no explicit size restriction on an offset from UTC, but there is an implicit limit imposed when using the
toString()
andfromString()
methods which use a ±hh:mm format, effectively limiting the range to ± 99 hours and 59 minutes and whole minutes only. Note that currently no time zone has an offset outside the range of ±14 hours and all known offsets are multiples of five minutes. Historical time zones have a wider range and may have offsets including seconds; these last cannot be faithfully represented in strings.- class TransitionResolution#
This enumeration is used to resolve datetime combinations which fall in
Timezone transitions
.When constructing a datetime, specified in terms of local time or a time-zone that has daylight-saving time, or revising one with
setDate()
,setTime()
orsetTimeZone()
, the given parameters may imply a time representation that either has no meaning or has two meanings in the zone. Such time representations are described as being in the transition. In either case, we can simply return an invalid datetime, to indicate that the operation is ill-defined. In the ambiguous case, we can alternatively select one of the two times that could be meant. When there is no meaning, we can select a time either side of it that might plausibly have been meant. For example, when advancing from an earlier time, we can select the time after the transition that is actually the specified amount of time after the earlier time in question. The options specified here configure how such selection is performed.Constant
Description
QDateTime.TransitionResolution.Reject
Treat any time in a transition as invalid. Either it really is, or it is ambiguous.
QDateTime.TransitionResolution.RelativeToBefore
Selects a time as if stepping forward from a time before the transition. This interprets the requested time using the offset in effect before the transition and, if necessary, converts the result to the offset in effect at the resulting time.
QDateTime.TransitionResolution.RelativeToAfter
Select a time as if stepping backward from a time after the transition. This interprets the requested time using the offset in effect after the transition and, if necessary, converts the result to the offset in effect at the resulting time.
QDateTime.TransitionResolution.PreferBefore
Selects a time before the transition,
QDateTime.TransitionResolution.PreferAfter
Selects a time after the transition.
QDateTime.TransitionResolution.PreferStandard
Selects a time on the standard time side of the transition.
QDateTime.TransitionResolution.PreferDaylightSaving
Selects a time on the daylight-saving-time side of the transition.
QDateTime.TransitionResolution.LegacyBehavior
An alias for RelativeToBefore, which is used as default for TransitionResolution parameters, as this most closely matches the behavior prior to Qt 6.7.
For
addDays()
,addMonths()
oraddYears()
, the behavior is and (mostly) was to useRelativeToBefore
if adding a positive adjustment andRelativeToAfter
if adding a negative adjustment.Note
In time zones where daylight-saving increases the offset from UTC in summer (known as “positive DST”), PreferStandard is an alias for RelativeToAfter and PreferDaylightSaving for RelativeToBefore. In time zones where the daylight-saving mechanism is a decrease in offset from UTC in winter (known as “negative DST”), the reverse applies, provided the operating system reports - as it does on most platforms - whether a datetime is in DST or standard time. For some platforms, where transition times are unavailable even for
TimeZone
datetimes,QTimeZone
is obliged to presume that the side with lower offset from UTC is standard time, effectively assuming positive DST.The following tables illustrate how a
QDateTime
constructor resolves a request for 02:30 on a day when local time has a transition between 02:00 and 03:00, with a nominal standard time LST and daylight-saving time LDT on the two sides, in the various possible cases. The transition type may be to skip an hour or repeat it. The type of transition and value of a parameterresolve
determine which actual time on the given date is selected. First, the common case of positive daylight-saving, where:Before
02:00–03:00
After
resolve
selected
LST
skip
LDT
RelativeToBefore
03:30 LDT
LST
skip
LDT
RelativeToAfter
01:30 LST
LST
skip
LDT
PreferBefore
01:30 LST
LST
skip
LDT
PreferAfter
03:30 LDT
LST
skip
LDT
PreferStandard
01:30 LST
LST
skip
LDT
PreferDaylightSaving
03:30 LDT
LDT
repeat
LST
RelativeToBefore
02:30 LDT
LDT
repeat
LST
RelativeToAfter
02:30 LST
LDT
repeat
LST
PreferBefore
02:30 LDT
LDT
repeat
LST
PreferAfter
02:30 LST
LDT
repeat
LST
PreferStandard
02:30 LST
LDT
repeat
LST
PreferDaylightSaving
02:30 LDT
Second, the case for negative daylight-saving, using LDT in winter and skipping an hour to transition to LST in summer, then repeating an hour at the transition back to winter:
LDT
skip
LST
RelativeToBefore
03:30 LST
LDT
skip
LST
RelativeToAfter
01:30 LDT
LDT
skip
LST
PreferBefore
01:30 LDT
LDT
skip
LST
PreferAfter
03:30 LST
LDT
skip
LST
PreferStandard
03:30 LST
LDT
skip
LST
PreferDaylightSaving
01:30 LDT
LST
repeat
LDT
RelativeToBefore
02:30 LST
LST
repeat
LDT
RelativeToAfter
02:30 LDT
LST
repeat
LDT
PreferBefore
02:30 LST
LST
repeat
LDT
PreferAfter
02:30 LDT
LST
repeat
LDT
PreferStandard
02:30 LST
LST
repeat
LDT
PreferDaylightSaving
02:30 LDT
Reject can be used to prompt relevant
QDateTime
APIs to return an invalid datetime object so that your code can deal with transitions for itself, for example by alerting a user to the fact that the datetime they have selected is in a transition interval, to offer them the opportunity to resolve a conflict or ambiguity. Code using this may well find the other options above useful to determine relevant information to use in its own (or the user’s) resolution. If the start or end of the transition, or the moment of the transition itself, is the right resolution,QTimeZone
‘s transition APIs can be used to obtain that information. You can determine whether the transition is a repeated or skipped interval by usingsecsTo()
to measure the actual time between noon on the previous and following days. The result will be less than 48 hours for a skipped interval (such as a spring-forward) and more than 48 hours for a repeated interval (such as a fall-back).Note
When a resolution other than Reject is specified, a valid
QDateTime
object is returned, if possible. If the requested date-time falls in a gap, the returned date-time will not have thetime()
requested - or, in some cases, thedate()
, if a whole day was skipped. You can thus detect when a gap is hit by comparingdate()
andtime()
to what was requested.Relation to other datetime software#
The Python programming language’s datetime APIs have a
fold
parameter that corresponds toRelativeToBefore
(fold = True
) andRelativeToAfter
(fold = False
).The
Temporal
proposal to replace JavaScript’sDate
offers four options for how to resolve a transition, as value for adisambiguation
parameter. Its'reject'
raises an exception, which roughly corresponds toReject
producing an invalid result. Its'earlier'
and'later'
options correspond toPreferBefore
andPreferAfter
. Its'compatible'
option corresponds toRelativeToBefore
(and Python’sfold = True
).See also
Timezone transitions
TransitionResolution
New in version 6.7.
- class YearRange#
This enumerated type describes the range of years (in the Gregorian calendar) representable by
QDateTime
:Constant
Description
QDateTime.YearRange.First
The later parts of this year are representable
QDateTime.YearRange.Last
The earlier parts of this year are representable
All dates strictly between these two years are also representable. Note, however, that the Gregorian Calendar has no year zero.
- __init__(date, time[, resolve=QDateTime.TransitionResolution.LegacyBehavior])#
- Parameters:
date –
QDate
time –
QTime
resolve –
TransitionResolution
This is an overloaded function.
Constructs a datetime with the given
date
andtime
, using local time.If
date
is valid andtime
is not, midnight will be used as the time. Ifdate
andtime
describe a moment close to a transition for local time,resolve
controls how that situation is resolved.Note
Prior to Qt 6.7, the version of this function lacked the
resolve
parameter so had no way to resolve the ambiguities related to transitions.- __init__(date, time, spec[, offsetSeconds=0])
Use
QDateTime(date, time)
orQDateTime(date, time, QTimeZone::fromSecondsAheadOfUtc(offsetSeconds))
.Constructs a datetime with the given
date
andtime
, using the time representation implied byspec
andoffsetSeconds
seconds.If
date
is valid andtime
is not, the time will be set to midnight.If
spec
is notOffsetFromUTC
thenoffsetSeconds
will be ignored. Ifspec
isOffsetFromUTC
andoffsetSeconds
is 0 then thetimeSpec()
will be set toUTC
, i.e. an offset of 0 seconds.If
spec
isTimeZone
then the spec will be set toLocalTime
, i.e. the current system time zone. To create aTimeZone
datetime use the correct constructor.If
date
lies outside the range of dates representable byQDateTime
, the result is invalid. Ifspec
isLocalTime
and the system’s time-zone skipped over the given date and time, the result is invalid.- __init__(date, time, timeZone[, resolve=QDateTime.TransitionResolution.LegacyBehavior])
- Parameters:
date –
QDate
time –
QTime
timeZone –
QTimeZone
resolve –
TransitionResolution
Constructs a datetime with the given
date
andtime
, using the time representation described bytimeZone
.If
date
is valid andtime
is not, the time will be set to midnight. IftimeZone
is invalid then the datetime will be invalid. Ifdate
andtime
describe a moment close to a transition fortimeZone
,resolve
controls how that situation is resolved.Note
Prior to Qt 6.7, the version of this function lacked the
resolve
parameter so had no way to resolve the ambiguities related to transitions.- __init__(other)
- Parameters:
other –
QDateTime
Constructs a copy of the
other
datetime.- __init__(arg__1, arg__2, arg__3, arg__4, arg__5, arg__6)
- Parameters:
arg__1 – int
arg__2 – int
arg__3 – int
arg__4 – int
arg__5 – int
arg__6 – int
- __init__(arg__1, arg__2, arg__3, arg__4, arg__5, arg__6, arg__7[, arg__8=Qt.LocalTime])
- Parameters:
arg__1 – int
arg__2 – int
arg__3 – int
arg__4 – int
arg__5 – int
arg__6 – int
arg__7 – int
arg__8 –
TimeSpec
- __init__(arg__1, arg__2, arg__3, arg__4, arg__5, arg__6, arg__7[, arg__8=Qt.LocalTime])
- Parameters:
arg__1 – int
arg__2 – int
arg__3 – int
arg__4 – int
arg__5 – int
arg__6 – int
arg__7 – int
arg__8 – int
- __init__()
Constructs a null datetime, nominally using local time.
A null datetime is invalid, since its date and time are invalid.
- __reduce__()#
- Return type:
object
- __repr__()#
- Return type:
object
Returns a
QDateTime
object containing a datetimendays
days later than the datetime of this object (or earlier ifndays
is negative).If the
timeSpec()
isLocalTime
orTimeZone
and the resulting date and time fall in the Standard Time to Daylight-Saving Time transition hour then the result will be just beyond this gap, in the direction of change. If the transition is at 2am and the clock goes forward to 3am, the result of aiming between 2am and 3am will be adjusted to fall before 2am (ifndays < 0
) or after 3am (otherwise).See also
daysTo()
addMonths()
addYears()
addSecs()
Timezone transitions
Returns a
QDateTime
object containing a datetimemsecs
milliseconds later than the datetime of this object (or earlier ifmsecs
is negative).If this datetime is invalid, an invalid datetime will be returned.
See also
Returns a
QDateTime
object containing a datetimenmonths
months later than the datetime of this object (or earlier ifnmonths
is negative).If the
timeSpec()
isLocalTime
orTimeZone
and the resulting date and time fall in the Standard Time to Daylight-Saving Time transition hour then the result will be just beyond this gap, in the direction of change. If the transition is at 2am and the clock goes forward to 3am, the result of aiming between 2am and 3am will be adjusted to fall before 2am (ifnmonths < 0
) or after 3am (otherwise).See also
daysTo()
addDays()
addYears()
addSecs()
Timezone transitions
Returns a
QDateTime
object containing a datetimes
seconds later than the datetime of this object (or earlier ifs
is negative).If this datetime is invalid, an invalid datetime will be returned.
See also
Returns a
QDateTime
object containing a datetimenyears
years later than the datetime of this object (or earlier ifnyears
is negative).If the
timeSpec()
isLocalTime
orTimeZone
and the resulting date and time fall in the Standard Time to Daylight-Saving Time transition hour then the result will be just beyond this gap, in the direction of change. If the transition is at 2am and the clock goes forward to 3am, the result of aiming between 2am and 3am will be adjusted to fall before 2am (ifnyears < 0
) or after 3am (otherwise).See also
daysTo()
addDays()
addMonths()
addSecs()
Timezone transitions
Returns the system clock’s current datetime, using the time representation described by
zone
. Ifzone
is omitted, local time is used.- static currentDateTime()
- Return type:
This is an overloaded function.
Returns the system clock’s current datetime, expressed in terms of UTC.
Equivalent to
currentDateTime(QTimeZone::UTC)
.- static currentMSecsSinceEpoch()#
- Return type:
int
Returns the current number of milliseconds since the start, in UTC, of the year 1970.
This number is like the POSIX time_t variable, but expressed in milliseconds instead of seconds.
- static currentSecsSinceEpoch()#
- Return type:
int
Returns the number of seconds since the start, in UTC, of the year 1970.
This number is like the POSIX time_t variable.
See also
Returns the date part of the datetime.
See also
Warning
This section contains snippets that were automatically translated from C++ to Python and may contain errors.
Returns the number of days from this datetime to the
other
datetime. The number of days is counted as the number of times midnight is reached between this datetime to theother
datetime. This means that a 10 minute difference from 23:55 to 0:05 the next day counts as one day.If the
other
datetime is earlier than this datetime, the value returned is negative.Example:
startDate = QDateTime(QDate(2012, 7, 6), QTime(8, 30, 0)) endDate = QDateTime(QDate(2012, 7, 7), QTime(16, 30, 0)) print("Days from startDate to endDate: ", startDate.daysTo(endDate)) startDate = QDateTime(QDate(2012, 7, 6), QTime(23, 55, 0)) endDate = QDateTime(QDate(2012, 7, 7), QTime(0, 5, 0)) print("Days from startDate to endDate: ", startDate.daysTo(endDate)) qSwap(startDate, endDate) # Make endDate before startDate. print("Days from startDate to endDate: ", startDate.daysTo(endDate))
- static fromMSecsSinceEpoch(msecs, timeZone)#
This is an overloaded function.
Returns a datetime representing a moment the given number
msecs
of milliseconds after the start, in UTC, of the year 1970, described as specified bytimeZone
. The default time representation is local time.Note that there are possible values for
msecs
that lie outside the valid range ofQDateTime
, both negative and positive. The behavior of this function is undefined for those values.- static fromMSecsSinceEpoch(msecs, spec[, offsetFromUtc=0])
This is an overloaded function.
Pass a
QTimeZone
instead, or omitspec
andoffsetSeconds
.Returns a datetime representing a moment the given number
msecs
of milliseconds after the start, in UTC, of the year 1970, described as specified byspec
andoffsetSeconds
.Note that there are possible values for
msecs
that lie outside the valid range ofQDateTime
, both negative and positive. The behavior of this function is undefined for those values.If the
spec
is notOffsetFromUTC
then theoffsetSeconds
will be ignored. If thespec
isOffsetFromUTC
and theoffsetSeconds
is 0 thenUTC
will be used as thespec
, since UTC has zero offset.If
spec
isTimeZone
thenLocalTime
will be used in its place, equivalent to using the current system time zone (but differently represented).- static fromMSecsSinceEpoch(msecs)
- Parameters:
msecs – int
- Return type:
This is an overloaded function.
This is an overloaded function.
- static fromSecsSinceEpoch(secs, spec[, offsetFromUtc=0])
This is an overloaded function.
Pass a
QTimeZone
instead, or omitspec
andoffsetSeconds
.Returns a datetime representing a moment the given number
secs
of seconds after the start, in UTC, of the year 1970, described as specified byspec
andoffsetSeconds
.Note that there are possible values for
secs
that lie outside the valid range ofQDateTime
, both negative and positive. The behavior of this function is undefined for those values.If the
spec
is notOffsetFromUTC
then theoffsetSeconds
will be ignored. If thespec
isOffsetFromUTC
and theoffsetSeconds
is 0 thenUTC
will be used as thespec
, since UTC has zero offset.If
spec
isTimeZone
thenLocalTime
will be used in its place, equivalent to using the current system time zone (but differently represented).- static fromSecsSinceEpoch(secs, timeZone)
This is an overloaded function.
Returns a datetime representing a moment the given number
secs
of seconds after the start, in UTC, of the year 1970, described as specified bytimeZone
. The default time representation is local time.Note that there are possible values for
secs
that lie outside the valid range ofQDateTime
, both negative and positive. The behavior of this function is undefined for those values.- 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
QDateTime
represented by thestring
, using theformat
given, or an invalid datetime if the string cannot be parsed.Uses the calendar
cal
if supplied, else Gregorian.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. In some cases, other fields may lead to the next or previous century being selected, to get a result consistent with all fields given. SeefromString()
for details.In addition to the expressions, recognized in the format string to represent parts of the date and time, by
fromString()
andfromString()
, this method supports:Expression
Output
t
the timezone (offset, name, “Z” or offset with “UTC” prefix)
tt
the timezone in offset format with no colon between hours and minutes (for example “+0200”)
ttt
the timezone in offset format with a colon between hours and minutes (for example “+02:00”)
tttt
the timezone name (for example “Europe/Berlin”). The name recognized are those known to
QTimeZone
, which may depend on the operating system in use.If no ‘t’ format specifier is present, the system’s local time-zone is used. For the defaults of all other fields, see
fromString()
andfromString()
.For example:
dateTime = QDateTime.fromString("1.30.1", "M.d.s") # dateTime is January 30 in 1900 at 00:00:01. dateTime = QDateTime.fromString("12", "yy") # dateTime is January 1 in 1912 at 00:00:00.
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.
time1 = QTime.fromString("131", "HHh") # time1 is 13:00:00 time1 = QTime.fromString("1apA", "1amAM") # time1 is 01:00:00 dateTime2 = QDateTime.fromString("M1d1y9800:01:02",() "'M'M'd'd'y'yyhh:mm:ss") # dateTime is 1 January 1998 00:01:02
If the format is not satisfied, an invalid
QDateTime
is returned. If the format is satisfied butstring
represents an invalid datetime (e.g. in a gap skipped by a time-zone transition), an validQDateTime
is returned, that represents a near-by datetime that is valid.The expressions that don’t have leading zeroes (d, M, h, m, s, z) will be greedy. This means that they will use two digits (or three, for z) even if this will put them outside the range and/or leave too few digits for other sections.
dateTime = QDateTime.fromString("130", "Mm") # invalid()
This could have meant 1 January 00:30.00 but the M will grab two digits.
Incorrectly specified fields of the
string
will cause an invalidQDateTime
to be returned. For example, consider the following code, where the two digit year 12 is read as 1912 (see the table below for all field defaults); the resulting datetime is invalid because 23 April 1912 was a Tuesday, not a Monday:string = "Monday, 23 April 12 22:51:41" format = "dddd, d MMMM yy hh:mm:ss" invalid = QDateTime.fromString(string, format)
The correct code is:
string = "Tuesday, 23 April 12 22:51:41" format = "dddd, d MMMM yy hh:mm:ss" valid = QDateTime.fromString(string, format)
Note
Day and month names as well as AM/PM indicators must be given in English (C locale). If localized month and day names or localized forms of AM/PM are to be recognized, use
system()
.toDateTime().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
'tttttt'
would match"Europe/BerlinEurope/Berlin"
and set the zone to Berlin time; if the datetime string contained “Europe/BerlinZ” it would “match” but produce an inconsistent result, leading to an invalid datetime.See also
- 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=Qt.TextDate])
- Parameters:
string – str
format –
DateFormat
- Return type:
Returns the
QDateTime
represented by thestring
, using theformat
given, or an invalid datetime if this is not possible.Note for
TextDate
: only English short month names (e.g. “Jan” in short form or “January” in long form) are recognized.See also
- static fromString(string, format, baseYear, cal)
This is an overloaded function.
- 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=Qt.TextDate])
- Parameters:
string – str
format –
DateFormat
- Return type:
This is an overloaded function.
- static fromString(string, format, baseYear, cal)
This is an overloaded function.
- isDaylightTime()#
- Return type:
bool
Returns if this datetime falls in Daylight-Saving Time.
If the
TimeSpec
is notLocalTime
orTimeZone
then will always return false.See also
- isNull()#
- Return type:
bool
Returns
true
if both the date and the time are null; otherwise returnsfalse
. A null datetime is invalid.- isValid()#
- Return type:
bool
Returns
true
if this datetime represents a definite moment, otherwisefalse
.A datetime is valid if both its date and its time are valid and the time representation used gives a valid meaning to their combination. When the time representation is a specific time-zone or local time, there may be times on some dates that the zone skips in its representation, as when a daylight-saving transition skips an hour (typically during a night in spring). For example, if DST ends at 2am with the clock advancing to 3am, then datetimes from 02:00:00 to 02:59:59.999 on that day are invalid.
Returns the number of milliseconds from this datetime to the
other
datetime. If theother
datetime is earlier than this datetime, the value returned is negative.Before performing the comparison, the two datetimes are converted to
UTC
to ensure that the result is correct if daylight-saving (DST) applies to one of the two datetimes and but not the other.Returns 0 if either datetime is invalid.
See also
- offsetFromUtc()#
- Return type:
int
Returns this datetime’s Offset From UTC in seconds.
The result depends on
timeSpec()
:Qt::UTC
The offset is 0.Qt::OffsetFromUTC
The offset is the value originally set.Qt::LocalTime
The local time’s offset from UTC is returned.Qt::TimeZone
The offset used by the time-zone is returned.
For the last two, the offset at this date and time will be returned, taking account of Daylight-Saving Offset. The offset is the difference between the local time or time in the given time-zone and UTC time; it is positive in time-zones ahead of UTC (East of The Prime Meridian), negative for those behind UTC (West of The Prime Meridian).
See also
Returns
true
iflhs
is different fromrhs
; otherwise returnsfalse
.Two datetimes are different if either the date, the time, or the time zone components are different. Since 5.14, all invalid datetimes are equal (and less than all valid datetimes).
See also
operator==()
Returns
true
iflhs
is earlier thanrhs
; otherwise returnsfalse
.Two datetimes are different if either the date, the time, or the time zone components are different. Since 5.14, all invalid datetimes are equal (and less than all valid datetimes).
See also
operator==()
Returns
true
iflhs
is earlier than or equal torhs
; otherwise returnsfalse
.Two datetimes are different if either the date, the time, or the time zone components are different. Since 5.14, all invalid datetimes are equal (and less than all valid datetimes).
See also
operator==()
Returns
true
iflhs
is the same asrhs
; otherwise returnsfalse
.Two datetimes are different if either the date, the time, or the time zone components are different. Since 5.14, all invalid datetimes are equal (and less than all valid datetimes).
See also
operator!=()
operator
operator
operator>()
operator>=()
Returns
true
iflhs
is later thanrhs
; otherwise returnsfalse
.Two datetimes are different if either the date, the time, or the time zone components are different. Since 5.14, all invalid datetimes are equal (and less than all valid datetimes).
See also
operator==()
Returns
true
iflhs
is later than or equal torhs
; otherwise returnsfalse
.Two datetimes are different if either the date, the time, or the time zone components are different. Since 5.14, all invalid datetimes are equal (and less than all valid datetimes).
See also
operator==()
Warning
This section contains snippets that were automatically translated from C++ to Python and may contain errors.
Returns the number of seconds from this datetime to the
other
datetime. If theother
datetime is earlier than this datetime, the value returned is negative.Before performing the comparison, the two datetimes are converted to
UTC
to ensure that the result is correct if daylight-saving (DST) applies to one of the two datetimes but not the other.Returns 0 if either datetime is invalid.
Example:
- setDate(date[, resolve=QDateTime.TransitionResolution.LegacyBehavior])#
- Parameters:
date –
QDate
resolve –
TransitionResolution
Sets the date part of this datetime to
date
.If no time is set yet, it is set to midnight. If
date
is invalid, thisQDateTime
becomes invalid.If
date
andtime()
describe a moment close to a transition for this datetime’s time representation,resolve
controls how that situation is resolved.Note
Prior to Qt 6.7, the version of this function lacked the
resolve
parameter so had no way to resolve the ambiguities related to transitions.See also
- setMSecsSinceEpoch(msecs)#
- Parameters:
msecs – int
Sets the datetime to represent a moment a given number,
msecs
, of milliseconds after the start, in UTC, of the year 1970.On systems that do not support time zones, this function will behave as if local time were
UTC
.Note that passing the minimum of
qint64
(std::numeric_limits<qint64>::min()
) tomsecs
will result in undefined behavior.- setOffsetFromUtc(offsetSeconds)#
- Parameters:
offsetSeconds – int
Use
setTimeZone
(fromSecondsAheadOfUtc
(offsetSeconds)) insteadSets the
timeSpec()
toOffsetFromUTC
and the offset tooffsetSeconds
. The datetime may refer to a different point in time.The maximum and minimum offset is 14 positive or negative hours. If
offsetSeconds
is larger or smaller than that, then the result is undefined.If
offsetSeconds
is 0 then thetimeSpec()
will be set toUTC
.- setSecsSinceEpoch(secs)#
- Parameters:
secs – int
Sets the datetime to represent a moment a given number,
secs
, of seconds after the start, in UTC, of the year 1970.On systems that do not support time zones, this function will behave as if local time were
UTC
.- setTime(time[, resolve=QDateTime.TransitionResolution.LegacyBehavior])#
- Parameters:
time –
QTime
resolve –
TransitionResolution
Sets the time part of this datetime to
time
. Iftime
is not valid, this function sets it to midnight. Therefore, it’s possible to clear any set time in aQDateTime
by setting it to a defaultQTime
:QDateTime dt = QDateTime::currentDateTime(); dt.setTime(QTime());
If
date()
andtime
describe a moment close to a transition for this datetime’s time representation,resolve
controls how that situation is resolved.Note
Prior to Qt 6.7, the version of this function lacked the
resolve
parameter so had no way to resolve the ambiguities related to transitions.See also
Warning
This section contains snippets that were automatically translated from C++ to Python and may contain errors.
Use
setTimeZone()
insteadSets the time specification used in this datetime to
spec
. The datetime may refer to a different point in time.If
spec
isOffsetFromUTC
then thetimeSpec()
will be set toUTC
, i.e. an effective offset of 0.If
spec
isTimeZone
then the spec will be set toLocalTime
, i.e. the current system time zone.Example:
local = QDateTime(QDateTime.currentDateTime()) print("Local time is:", local) UTC = QDateTime(local) UTC.setTimeSpec(Qt.UTC) print("UTC time is:", UTC) print("There are", local.secsTo(UTC), "seconds difference between the datetimes.")
- setTimeZone(toZone[, resolve=QDateTime.TransitionResolution.LegacyBehavior])#
- Parameters:
toZone –
QTimeZone
resolve –
TransitionResolution
Sets the time zone used in this datetime to
toZone
.The datetime may refer to a different point in time. It uses the time representation of
toZone
, which may change the meaning of its unchangeddate()
andtime()
.If
toZone
is invalid then the datetime will be invalid. Otherwise, this datetime’stimeSpec()
after the call will matchtoZone.timeSpec()
.If
date()
andtime()
describe a moment close to a transition fortoZone
,resolve
controls how that situation is resolved.Note
Prior to Qt 6.7, the version of this function lacked the
resolve
parameter so had no way to resolve the ambiguities related to transitions.See also
Swaps this datetime with
other
. This operation is very fast and never fails.Returns the time part of the datetime.
See also
Returns a
QTimeZone
identifying how this datetime represents time.The
timeSpec()
of the returnedQTimeZone
will coincide with that of this datetime; if it is notTimeZone
then the returnedQTimeZone
is a time representation. When theirtimeSpec()
isOffsetFromUTC
, the returnedQTimeZone
‘s fixedSecondsAheadOfUtc() supplies the offset. WhentimeSpec()
isTimeZone
, theQTimeZone
object itself is the full representation of that time zone.See also
Returns the time specification of the datetime.
This classifies its time representation as local time, UTC, a fixed offset from UTC (without indicating the offset) or a time zone (without giving the details of that time zone). Equivalent to
timeRepresentation().timeSpec()
.See also
Returns the time zone of the datetime.
The result is the same as
timeRepresentation().asBackendZone()
. In all cases, the result’stimeSpec()
isTimeZone
.When
timeSpec()
isLocalTime
, the result will describe local time at the time this method was called. It will not reflect subsequent changes to the system time zone, even when theQDateTime
from which it was obtained does.- timeZoneAbbreviation()#
- Return type:
str
Returns the Time Zone Abbreviation for this datetime.
The returned string depends on
timeSpec()
:For
UTC
it is “UTC”.For
OffsetFromUTC
it will be in the format “UTC±00:00”.For
LocalTime
, the host system is queried.
Note
The abbreviation is not guaranteed to be unique, i.e. different time zones may have the same abbreviation. For
LocalTime
andTimeZone
, when returned by the host system, the abbreviation may be localized.See also
Warning
This section contains snippets that were automatically translated from C++ to Python and may contain errors.
Returns a copy of this datetime converted to local time.
The result represents the same moment in time as, and is equal to, this datetime.
Example:
UTC = QDateTime(QDateTime.currentDateTimeUtc()) local = QDateTime(UTC.toLocalTime()) print("UTC time is:", UTC) print("Local time is:", local) print("No difference between times:", UTC.secsTo(local))
See also
- toMSecsSinceEpoch()#
- Return type:
int
Returns the datetime as a number of milliseconds after the start, in UTC, of the year 1970.
On systems that do not support time zones, this function will behave as if local time were
UTC
.The behavior for this function is undefined if the datetime stored in this object is not valid. However, for all valid dates, this function returns a unique value.
Returns a copy of this datetime converted to a spec of
OffsetFromUTC
with the givenoffsetSeconds
. Equivalent totoTimeZone(QTimeZone::fromSecondsAheadOfUtc(offsetSeconds))
.If the
offsetSeconds
equals 0 then a UTC datetime will be returned.The result represents the same moment in time as, and is equal to, this datetime.
- toPython()#
- Return type:
object
- toSecsSinceEpoch()#
- Return type:
int
Returns the datetime as a number of seconds after the start, in UTC, of the year 1970.
On systems that do not support time zones, this function will behave as if local time were
UTC
.The behavior for this function is undefined if the datetime stored in this object is not valid. However, for all valid dates, this function returns a unique value.
- 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=Qt.TextDate])
- Parameters:
format –
DateFormat
- Return type:
str
This is an overloaded function.
Returns the datetime as a string in the
format
given.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 “Wed May 20 03:40:13 1998”. 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-ddTHH:mm:ss[Z|±HH:mm], depending on thetimeSpec()
of theQDateTime
. If thetimeSpec()
isUTC
, Z will be appended to the string; if thetimeSpec()
isOffsetFromUTC
, the offset in hours and minutes from UTC will be appended to the string. To include milliseconds in the ISO 8601 date, use theformat
ISODateWithMs
, which corresponds to yyyy-MM-ddTHH:mm:ss.zzz[Z|±HH:mm].If the
format
isRFC2822Date
, the string is formatted following RFC 2822.If the datetime 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
Warning
This section contains snippets that were automatically translated from C++ to Python and may contain errors.
Use
toTimeZone()
instead.Returns a copy of this datetime converted to the given time
spec
.The result represents the same moment in time as, and is equal to, this datetime.
If
spec
isOffsetFromUTC
then it is set toUTC
. To set to a fixed offset from UTC, usetoTimeZone()
ortoOffsetFromUtc()
.If
spec
isTimeZone
then it is set toLocalTime
, i.e. the local Time Zone. To set a specified time-zone, usetoTimeZone()
.Example:
local = QDateTime(QDateTime.currentDateTime()) UTC = QDateTime(local.toTimeSpec(Qt.UTC)) print("Local time is:", local) print("UTC time is:", UTC) print("No difference between times:", local.secsTo(UTC))
See also
Warning
This section contains snippets that were automatically translated from C++ to Python and may contain errors.
Returns a copy of this datetime converted to the given
timeZone
.The result represents the same moment in time as, and is equal to, this datetime.
The result describes the moment in time in terms of
timeZone
's time representation. For example:local = QDateTime(QDateTime.currentDateTime()) UTC = QDateTime(local.toTimeSpec(QTimeZone.UTC)) print("Local time is:", local) print("UTC time is:", UTC) print("No difference between times represented:", local.secsTo(UTC))
If
timeZone
is invalid then the datetime will be invalid. Otherwise the returned datetime’stimeSpec()
will matchtimeZone.timeSpec()
.Warning
This section contains snippets that were automatically translated from C++ to Python and may contain errors.
Returns a copy of this datetime converted to UTC.
The result represents the same moment in time as, and is equal to, this datetime.
Example:
local = QDateTime(QDateTime.currentDateTime()) UTC = QDateTime(local.toUTC()) print("Local time is:", local) print("UTC time is:", UTC) print("No difference between times:", local.secsTo(UTC))
See also