QDateTime Class Reference
|
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.
QTime time1 = QTime::fromString("131", "HHh"); // time1 is 13:00:00 QTime time1 = QTime::fromString("1apA", "1amAM"); // time1 is 01:00:00 QDateTime 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. 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.
QDateTime 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:
QDateTime dateTime = QDateTime::fromString("1.30.1", "M.d.s");
// dateTime is January 30 in 1900 at 00:00:01.
QDateTime::toString() QTime::toString()
See also QDate::fromString(), QTime::fromString(), and QDate::toString().
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.
This function was introduced in Qt 4.2.
See also toTime_t() and setTime_t().
Returns true if both the date and the time are null; otherwise returns false. A null datetime is invalid.
See also QDate::isNull(), QTime::isNull(), and isValid().
Returns true if both the date and the time are valid; otherwise returns false.
See also QDate::isValid() and QTime::isValid().
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:
QDateTime now = QDateTime::currentDateTime(); QDateTime xmas(QDate(now.date().year(), 12, 25), QTime(0, 0)); qDebug("There are %d seconds to Christmas", now.secsTo(xmas));
See also addSecs(), daysTo(), and QTime::secsTo().
Sets the date part of this datetime to date. If no time is set, it is set to midnight.
See also date(), setTime(), and setTimeSpec().
Sets the time part of this datetime to time.
See also time(), setDate(), and setTimeSpec().
Sets the time specification used in this datetime to spec.
See also timeSpec(), setDate(), setTime(), and Qt::TimeSpec.
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.
See also toTime_t().
Returns the time part of the datetime.
See also setTime(), date(), and timeSpec().
Returns the time specification of the datetime.
See also setTimeSpec(), date(), time(), and Qt::TimeSpec.
Returns a datetime containing the date and time information in this datetime, but specified using the Qt::LocalTime definition.
See also toTimeSpec().
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 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.
See also QDate::toString() and QTime::toString().
This is an overloaded member function, provided for convenience.
Returns the datetime as a string in the format given.
If the format is Qt::TextDate, the string is formatted in the default way. QDate::shortDayName(), QDate::shortMonthName(), and QTime::toString() are used to generate the string, so the day and month names will be localized names. An example of this formatting is "Wed May 20 03:40:13 1998".
If the format is Qt::ISODate, the string format corresponds to the ISO 8601 extended specification for representations of dates and times, taking the form YYYY-MM-DDTHH:MM:SS.
If the format is Qt::SystemLocaleShortDate or Qt::SystemLocaleLongDate, the string format depends on the locale settings of the system. Identical to calling QLocale::system().toString(datetime, QLocale::ShortFormat) or QLocale::system().toString(datetime, QLocale::LongFormat).
If the format is Qt::DefaultLocaleShortDate or Qt::DefaultLocaleLongDate, the string format depends on the default application locale. This is the locale set with QLocale::setDefault(), or the system locale if no default locale has been set. Identical to calling QLocale().toString(datetime, QLocale::ShortFormat) or QLocale().toString(datetime, QLocale::LongFormat).
If the datetime is invalid, an empty string will be returned.
Warning: The Qt::ISODate format is only valid for years in the range 0 to 9999. This restriction may apply to locale-aware formats as well, depending on the locale settings.
See also QDate::toString(), QTime::toString(), and Qt::DateFormat.
Returns a copy of this datetime configured to use the given time specification.
See also timeSpec(), toUTC(), and toLocalTime().
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.
See also setTime_t().
Returns a datetime containing the date and time information in this datetime, but specified using the Qt::UTC definition.
See also toTimeSpec().
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 operator==().
Returns true if this datetime is earlier than the other datetime; otherwise returns false.
Returns true if this datetime is earlier than or equal to the other datetime; otherwise returns false.
Makes a copy of the other datetime and returns a reference to the copy.
Returns true if this datetime is equal to the other datetime; otherwise returns false.
Note: This function compares for strict equality of the QDateTime object. Use QDateTime::toUTC(), instead if you would like to compare times.
See also operator!=().
Returns true if this datetime is later than the other datetime; otherwise returns false.
Returns true if this datetime is later than or equal to the other datetime; otherwise returns false.
This is an overloaded member function, provided for convenience.
Writes dateTime to the out stream.
See also Format of the QDataStream operators.
This is an overloaded member function, provided for convenience.
Reads a datetime from the stream in into dateTime.
See also Format of the QDataStream operators.
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