QDateTime

Synopsis

Functions

Static functions

Detailed Description

The PySide.QtCore.QDateTime class provides date and time functions.

A PySide.QtCore.QDateTime object contains a calendar date and a clock time (a “datetime”). It is a combination of the PySide.QtCore.QDate and PySide.QtCore.QTime 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.

A PySide.QtCore.QDateTime object is typically created either by giving a date and time explicitly in the constructor, or by using the static function PySide.QtCore.QDateTime.currentDateTime() that returns a PySide.QtCore.QDateTime object set to the system clock’s time. The date and time can be changed with PySide.QtCore.QDateTime.setDate() and PySide.QtCore.QDateTime.setTime() . A datetime can also be set using the PySide.QtCore.QDateTime.setTime_t() function that takes a POSIX-standard “number of seconds since 00:00:00 on January 1, 1970” value. The PySide.QtCore.QDateTime.fromString() function returns a PySide.QtCore.QDateTime , given a string and a date format used to interpret the date within the string.

The PySide.QtCore.QDateTime.date() and PySide.QtCore.QDateTime.time() functions provide access to the date and time parts of the datetime. The same information is provided in textual format by the PySide.QtCore.QDateTime.toString() function.

PySide.QtCore.QDateTime provides a full set of operators to compare two PySide.QtCore.QDateTime objects where smaller means earlier and larger means later.

You can increment (or decrement) a datetime by a given number of milliseconds using PySide.QtCore.QDateTime.addMSecs() , seconds using PySide.QtCore.QDateTime.addSecs() , or days using PySide.QtCore.QDateTime.addDays() . Similarly you can use PySide.QtCore.QDateTime.addMonths() and PySide.QtCore.QDateTime.addYears() . The PySide.QtCore.QDateTime.daysTo() function returns the number of days between two datetimes, PySide.QtCore.QDateTime.secsTo() returns the number of seconds between two datetimes, and PySide.QtCore.QDateTime.msecsTo() returns the number of milliseconds between two datetimes.

PySide.QtCore.QDateTime can store datetimes as local time or as UTC . QDateTime.currentDateTime() returns a PySide.QtCore.QDateTime expressed as local time; use PySide.QtCore.QDateTime.toUTC() to convert it to UTC. You can also use PySide.QtCore.QDateTime.timeSpec() to find out if a PySide.QtCore.QDateTime object stores a UTC time or a local time. Operations such as PySide.QtCore.QDateTime.addSecs() and PySide.QtCore.QDateTime.secsTo() are aware of daylight saving time (DST).

Note

PySide.QtCore.QDateTime does not account for leap seconds.

Use of Gregorian and Julian Calendars

PySide.QtCore.QDate uses the Gregorian calendar in all locales, beginning on the date 15 October 1582. For dates up to and including 4 October 1582, the Julian calendar is used. This means there is a 10-day gap in the internal calendar between the 4th and the 15th of October 1582. When you use PySide.QtCore.QDateTime for dates in that epoch, the day after 4 October 1582 is 15 October 1582, and the dates in the gap are invalid.

The Julian to Gregorian changeover date used here is the date when the Gregorian calendar was first introduced, by Pope Gregory XIII. That change was not universally accepted and some localities only executed it at a later date (if at all). PySide.QtCore.QDateTime doesn’t take any of these historical facts into account. If an application must support a locale-specific dating system, it must do so on its own, remembering to convert the dates using the Julian day.

No Year 0

There is no year 0. Dates in that year are considered invalid. The year -1 is the year “1 before Christ” or “1 before current era.” The day before 0001-01-01 is December 31st, 1 BCE.

Range of Valid Dates

The range of valid dates is from January 2nd, 4713 BCE, to sometime in the year 11 million CE. The Julian Day returned by QDate.toJulianDay() is a number in the contiguous range from 1 to overflow , even across PySide.QtCore.QDateTime ‘s “date holes”. It is suitable for use in applications that must convert a PySide.QtCore.QDateTime to a date in another calendar system, e.g., Hebrew, Islamic or Chinese.

The Gregorian calendar was introduced in different places around the world on different dates. PySide.QtCore.QDateTime uses PySide.QtCore.QDate to store the date, so it uses the Gregorian calendar for all locales, beginning on the date 15 October 1582. For dates up to and including 4 October 1582, PySide.QtCore.QDateTime uses the Julian calendar. This means there is a 10-day gap in the PySide.QtCore.QDateTime calendar between the 4th and the 15th of October 1582. When you use PySide.QtCore.QDateTime for dates in that epoch, the day after 4 October 1582 is 15 October 1582, and the dates in the gap are invalid.

Use of System Timezone

PySide.QtCore.QDateTime uses the system’s time zone information to determine the offset of local time from UTC. If the system is not configured correctly or not up-to-date, PySide.QtCore.QDateTime will give wrong results as well.

Daylight Savings Time (DST)

PySide.QtCore.QDateTime takes into account the system’s time zone information when dealing with DST. On modern Unix systems, this means it applies the correct historical DST data whenever possible. On Windows and Windows CE, where the system doesn’t support historical DST data, historical accuracy is not maintained with respect to DST.

The range of valid dates taking DST into account is 1970-01-01 to the present, and rules are in place for handling DST correctly until 2037-12-31, but these could change. For dates falling outside that range, PySide.QtCore.QDateTime makes a best guess using the rules for year 1970 or 2037, but we can’t guarantee accuracy. This means PySide.QtCore.QDateTime doesn’t take into account changes in a locale’s time zone before 1970, even if the system’s time zone database supports that information.

class PySide.QtCore.QDateTime
class PySide.QtCore.QDateTime(arg__1)
class PySide.QtCore.QDateTime(arg__1, arg__2[, spec=Qt.LocalTime])
class PySide.QtCore.QDateTime(other)
class PySide.QtCore.QDateTime(arg__1, arg__2, arg__3, arg__4, arg__5, arg__6)
class PySide.QtCore.QDateTime(arg__1, arg__2, arg__3, arg__4, arg__5, arg__6, arg__7[, arg__8=Qt.LocalTime])
Parameters:

Constructs a null datetime (i.e. null date and null time). A null datetime is invalid, since the date is invalid.

Constructs a datetime with the given date , a valid time(00:00:00.000), and sets the PySide.QtCore.QDateTime.timeSpec() to Qt.LocalTime .

Constructs a copy of the other datetime.

PySide.QtCore.QDateTime.__reduce__()
Return type:PyObject
PySide.QtCore.QDateTime.__repr__()
Return type:PyObject
PySide.QtCore.QDateTime.addDays(days)
Parameters:daysPySide.QtCore.int
Return type:PySide.QtCore.QDateTime

Returns a PySide.QtCore.QDateTime object containing a datetime ndays days later than the datetime of this object (or earlier if ndays is negative).

PySide.QtCore.QDateTime.addMSecs(msecs)
Parameters:msecsPySide.QtCore.qint64
Return type:PySide.QtCore.QDateTime

Returns a PySide.QtCore.QDateTime object containing a datetime msecs miliseconds later than the datetime of this object (or earlier if msecs is negative).

PySide.QtCore.QDateTime.addMonths(months)
Parameters:monthsPySide.QtCore.int
Return type:PySide.QtCore.QDateTime

Returns a PySide.QtCore.QDateTime object containing a datetime nmonths months later than the datetime of this object (or earlier if nmonths is negative).

PySide.QtCore.QDateTime.addSecs(secs)
Parameters:secsPySide.QtCore.int
Return type:PySide.QtCore.QDateTime

Returns a PySide.QtCore.QDateTime object containing a datetime s seconds later than the datetime of this object (or earlier if s is negative).

PySide.QtCore.QDateTime.addYears(years)
Parameters:yearsPySide.QtCore.int
Return type:PySide.QtCore.QDateTime

Returns a PySide.QtCore.QDateTime object containing a datetime nyears years later than the datetime of this object (or earlier if nyears is negative).

static PySide.QtCore.QDateTime.currentDateTime()
Return type:PySide.QtCore.QDateTime

Returns the current datetime, as reported by the system clock, in the local time zone.

static PySide.QtCore.QDateTime.currentDateTimeUtc()
Return type:PySide.QtCore.QDateTime

Returns the current datetime, as reported by the system clock, in UTC.

static PySide.QtCore.QDateTime.currentMSecsSinceEpoch()
Return type:PySide.QtCore.qint64

Returns the number of milliseconds since 1970-01-01T00:00:00 Universal Coordinated Time. This number is like the POSIX time_t variable, but expressed in milliseconds instead.

PySide.QtCore.QDateTime.date()
Return type:PySide.QtCore.QDate

Returns the date part of the datetime.

PySide.QtCore.QDateTime.daysTo(arg__1)
Parameters:arg__1PySide.QtCore.QDateTime
Return type:PySide.QtCore.int

Returns the number of days from this datetime to the other datetime. If the other datetime is earlier than this datetime, the value returned is negative.

static PySide.QtCore.QDateTime.fromMSecsSinceEpoch(msecs)
Parameters:msecsPySide.QtCore.qint64
Return type:PySide.QtCore.QDateTime

Returns a datetime whose date and time are the number of milliseconds, msecs , that have passed since 1970-01-01T00:00:00.000, Coordinated Universal Time ( Qt.UTC ). On systems that do not support time zones, the time will be set as if local time were Qt.UTC .

Note that there are possible values for msecs that lie outside the valid range of PySide.QtCore.QDateTime , both negative and positive. The behavior of this function is undefined for those values.

static PySide.QtCore.QDateTime.fromString(s, format)
Parameters:
  • s – unicode
  • format – unicode
Return type:

PySide.QtCore.QDateTime

Returns the PySide.QtCore.QDateTime represented by the string , using the format given, or an invalid datetime if the string cannot be parsed.

These expressions may be used for the date part of the format string:

Expression Output
d the day as number without a leading zero (1 to 31)
dd the day as number with a leading zero (01 to 31)
ddd the abbreviated localized day name (e.g. ‘Mon’ to ‘Sun’). Uses QDate.shortDayName() .
dddd the long localized day name (e.g. ‘Monday’ to ‘Sunday’). Uses QDate.longDayName() .
M the month as number without a leading zero (1-12)
MM the month as number with a leading zero (01-12)
MMM the abbreviated localized month name (e.g. ‘Jan’ to ‘Dec’). Uses QDate.shortMonthName() .
MMMM the long localized month name (e.g. ‘January’ to ‘December’). Uses QDate.longMonthName() .
yy the year as two digit number (00-99)
yyyy the year as four digit number

Note

Unlike the other version of this function, day and month names must be given in the user’s local language. It is only possible to use the English names if the user’s language is English.

These expressions may be used for the time part of the format string:

Expression Output
h the hour without a leading zero (0 to 23 or 1 to 12 if AM/PM display)
hh the hour with a leading zero (00 to 23 or 01 to 12 if AM/PM display)
H the hour without a leading zero (0 to 23, even with AM/PM display)
HH the hour with a leading zero (00 to 23, even with AM/PM display)
m the minute without a leading zero (0 to 59)
mm the minute with a leading zero (00 to 59)
s the second without a leading zero (0 to 59)
ss the second with a leading zero (00 to 59)
z the milliseconds without leading zeroes (0 to 999)
zzz the milliseconds with leading zeroes (000 to 999)
AP or A interpret as an AM/PM time. AP must be either “AM” or “PM”.
ap or a Interpret as an AM/PM time. ap must be either “am” or “pm”.

All other input characters will be treated as text. Any sequence of characters that are enclosed in singlequotes will also be treated as text and not be used as an expression.

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 PySide.QtCore.QDateTime is returned. 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 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.

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

Field Default value
Year 1900
Month 1 (January)
Day 1
Hour 0
Minute 0
Second 0

For example:

dateTime = QDateTime.fromString("1.30.1", "M.d.s")
# dateTime is January 30 in 1900 at 00:00:01.

QDateTime.toString() QTime.toString()

static PySide.QtCore.QDateTime.fromString(s[, f=Qt.TextDate])
Parameters:
Return type:

PySide.QtCore.QDateTime

static PySide.QtCore.QDateTime.fromTime_t(secsSince1Jan1970UTC)
Parameters:secsSince1Jan1970UTCPySide.QtCore.uint
Return type:PySide.QtCore.QDateTime

Returns a datetime whose date and time are the number of seconds that have passed since 1970-01-01T00:00:00, Coordinated Universal Time ( Qt.UTC ). On systems that do not support time zones, the time will be set as if local time were Qt.UTC .

PySide.QtCore.QDateTime.isNull()
Return type:PySide.QtCore.bool

Returns true if both the date and the time are null; otherwise returns false. A null datetime is invalid.

PySide.QtCore.QDateTime.isValid()
Return type:PySide.QtCore.bool

Returns true if both the date and the time are valid; otherwise returns false.

PySide.QtCore.QDateTime.msecsTo(arg__1)
Parameters:arg__1PySide.QtCore.QDateTime
Return type:PySide.QtCore.qint64

Returns the number of milliseconds from this datetime to the other datetime. If the other datetime is earlier than this datetime, the value returned is negative.

Before performing the comparison, the two datetimes are converted to Qt.UTC to ensure that the result is correct if one of the two datetimes has daylight saving time (DST) and the other doesn’t.

PySide.QtCore.QDateTime.__ne__(other)
Parameters:otherPySide.QtCore.QDateTime
Return type:PySide.QtCore.bool

Returns true if this datetime is different from the other datetime; otherwise returns false.

Two datetimes are different if either the date, the time, or the time zone components are different.

See also

PySide.QtCore.QDateTime.operator==()

PySide.QtCore.QDateTime.__lt__(other)
Parameters:otherPySide.QtCore.QDateTime
Return type:PySide.QtCore.bool

Returns true if this datetime is earlier than the other datetime; otherwise returns false.

PySide.QtCore.QDateTime.__le__(other)
Parameters:otherPySide.QtCore.QDateTime
Return type:PySide.QtCore.bool

Returns true if this datetime is earlier than or equal to the other datetime; otherwise returns false.

PySide.QtCore.QDateTime.__eq__(other)
Parameters:otherPySide.QtCore.QDateTime
Return type:PySide.QtCore.bool

Returns true if this datetime is equal to the other datetime; otherwise returns false.

See also

PySide.QtCore.QDateTime.operator!=()

PySide.QtCore.QDateTime.__gt__(other)
Parameters:otherPySide.QtCore.QDateTime
Return type:PySide.QtCore.bool

Returns true if this datetime is later than the other datetime; otherwise returns false.

PySide.QtCore.QDateTime.__ge__(other)
Parameters:otherPySide.QtCore.QDateTime
Return type:PySide.QtCore.bool

Returns true if this datetime is later than or equal to the other datetime; otherwise returns false.

PySide.QtCore.QDateTime.secsTo(arg__1)
Parameters:arg__1PySide.QtCore.QDateTime
Return type:PySide.QtCore.int

Returns the number of seconds from this datetime to the other datetime. If the other datetime is earlier than this datetime, the value returned is negative.

Before performing the comparison, the two datetimes are converted to Qt.UTC to ensure that the result is correct if one of the two datetimes has daylight saving time (DST) and the other doesn’t.

Example:

now = QDateTime.currentDateTime()
xmas(QDate(now.date().year(), 12, 25), QTime(0, 0))
print("There are %d seconds to Christmas" % now.secsTo(xmas))
PySide.QtCore.QDateTime.setDate(date)
Parameters:datePySide.QtCore.QDate

Sets the date part of this datetime to date . If no time is set, it is set to midnight.

PySide.QtCore.QDateTime.setMSecsSinceEpoch(msecs)
Parameters:msecsPySide.QtCore.qint64

Sets the date and time given the number of milliseconds,``msecs`` , that have passed since 1970-01-01T00:00:00.000, Coordinated Universal Time ( Qt.UTC ). On systems that do not support time zones this function will behave as if local time were Qt.UTC .

Note that there are possible values for msecs that lie outside the valid range of PySide.QtCore.QDateTime , both negative and positive. The behavior of this function is undefined for those values.

PySide.QtCore.QDateTime.setTime(time)
Parameters:timePySide.QtCore.QTime

Sets the time part of this datetime to time .

PySide.QtCore.QDateTime.setTimeSpec(spec)
Parameters:specPySide.QtCore.Qt.TimeSpec
PySide.QtCore.QDateTime.setTime_t(secsSince1Jan1970UTC)
Parameters:secsSince1Jan1970UTCPySide.QtCore.uint

Sets the date and time given the number of seconds that have passed since 1970-01-01T00:00:00, Coordinated Universal Time ( Qt.UTC ). On systems that do not support time zones this function will behave as if local time were Qt.UTC .

PySide.QtCore.QDateTime.setUtcOffset(seconds)
Parameters:secondsPySide.QtCore.int

Sets the offset from UTC to seconds , and also sets PySide.QtCore.QDateTime.timeSpec() to Qt.OffsetFromUTC .

The maximum and minimum offset is 14 positive or negative hours. If seconds is larger or smaller than that, the result is undefined.

0 as offset is identical to UTC. Therefore, if seconds is 0, the PySide.QtCore.QDateTime.timeSpec() will be set to Qt.UTC . Hence the UTC offset always relates to UTC, and can never relate to local time.

PySide.QtCore.QDateTime.time()
Return type:PySide.QtCore.QTime

Returns the time part of the datetime.

PySide.QtCore.QDateTime.timeSpec()
Return type:PySide.QtCore.Qt.TimeSpec

Returns the time specification of the datetime.

PySide.QtCore.QDateTime.toLocalTime()
Return type:PySide.QtCore.QDateTime

Returns a datetime containing the date and time information in this datetime, but specified using the Qt.LocalTime definition.

PySide.QtCore.QDateTime.toMSecsSinceEpoch()
Return type:PySide.QtCore.qint64

Returns the datetime as the number of milliseconds that have passed since 1970-01-01T00:00:00.000, Coordinated Universal Time ( Qt.UTC ).

On systems that do not support time zones, this function will behave as if local time were Qt.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.

PySide.QtCore.QDateTime.toPython()
Return type:PyObject
PySide.QtCore.QDateTime.toString(format)
Parameters:format – unicode
Return type:unicode

Returns the datetime as a string. The format parameter determines the format of the result string.

These expressions may be used for the date:

Expression Output
d the day as number without a leading zero (1 to 31)
dd the day as number with a leading zero (01 to 31)
ddd the abbreviated localized day name (e.g. ‘Mon’ to ‘Sun’). Uses QDate.shortDayName() .
dddd the long localized day name (e.g. ‘Monday’ to ‘ Qt.Sunday ‘). Uses QDate.longDayName() .
M the month as number without a leading zero (1-12)
MM the month as number with a leading zero (01-12)
MMM the abbreviated localized month name (e.g. ‘Jan’ to ‘Dec’). Uses QDate.shortMonthName() .
MMMM the long localized month name (e.g. ‘January’ to ‘December’). Uses QDate.longMonthName() .
yy the year as two digit number (00-99)
yyyy the year as four digit number

These expressions may be used for the time:

Expression Output
h the hour without a leading zero (0 to 23 or 1 to 12 if AM/PM display)
hh the hour with a leading zero (00 to 23 or 01 to 12 if AM/PM display)
m the minute without a leading zero (0 to 59)
mm the minute with a leading zero (00 to 59)
s the second without a leading zero (0 to 59)
ss the second with a leading zero (00 to 59)
z the milliseconds without leading zeroes (0 to 999)
zzz the milliseconds with leading zeroes (000 to 999)
AP use AM/PM display. AP will be replaced by either “AM” or “PM”.
ap use am/pm display. ap will be replaced by either “am” or “pm”.

All other input characters will be ignored. Any sequence of characters that are enclosed in singlequotes will be treated as text and not be used as an expression. Two consecutive singlequotes (“’‘”) are replaced by a singlequote in the output.

Example format strings (assumed that the PySide.QtCore.QDateTime is 21 May 2001 14:13:09):

Format Result
dd.MM.yyyy 21.05.2001
ddd MMMM d yy Tue May 21 01
hh:mm:ss.zzz 14:13:09.042
h:m:s ap 2:13:9 pm

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

PySide.QtCore.QDateTime.toString([f=Qt.TextDate])
Parameters:fPySide.QtCore.Qt.DateFormat
Return type:unicode
PySide.QtCore.QDateTime.toTimeSpec(spec)
Parameters:specPySide.QtCore.Qt.TimeSpec
Return type:PySide.QtCore.QDateTime
PySide.QtCore.QDateTime.toTime_t()
Return type:PySide.QtCore.uint

Returns the datetime as the number of seconds that have passed since 1970-01-01T00:00:00, Coordinated Universal Time ( Qt.UTC ).

On systems that do not support time zones, this function will behave as if local time were Qt.UTC .

Note

This function returns a 32-bit unsigned integer, so it does not support dates before 1970, but it does support dates after 2038-01-19T03:14:06, which may not be valid time_t values. Be careful when passing those time_t values to system functions, which could interpret them as negative dates.

If the date is outside the range 1970-01-01T00:00:00 to 2106-02-07T06:28:14, this function returns -1 cast to an unsigned integer (i.e., 0xFFFFFFFF).

To get an extended range, use PySide.QtCore.QDateTime.toMSecsSinceEpoch() .

PySide.QtCore.QDateTime.toUTC()
Return type:PySide.QtCore.QDateTime

Returns a datetime containing the date and time information in this datetime, but specified using the Qt.UTC definition.

PySide.QtCore.QDateTime.utcOffset()
Return type:PySide.QtCore.int

Returns the UTC offset in seconds. If the PySide.QtCore.QDateTime.timeSpec() isn’t Qt.OffsetFromUTC , 0 is returned. However, since 0 is a valid UTC offset the return value of this function cannot be used to determine whether a PySide.QtCore.QDateTime.utcOffset() is used or is valid, PySide.QtCore.QDateTime.timeSpec() must be checked.

Likewise, if this PySide.QtCore.QDateTime.QDateTime() is invalid or if PySide.QtCore.QDateTime.timeSpec() isn’t Qt.OffsetFromUTC , 0 is returned.

The UTC offset only applies if the PySide.QtCore.QDateTime.timeSpec() is Qt.OffsetFromUTC .