QgsDateTimeStatisticalSummary Class Reference

Calculator for summary statistics and aggregates for a list of datetimes. More...

#include <qgsdatetimestatisticalsummary.h>

Public Types
enum	Statistic {   Count = 1, CountDistinct = 2, CountMissing = 4, Min = 8,   Max = 16, Range = 32, All = Count | CountDistinct | CountMissing | Min | Max | Range }
	Enumeration of flags that specify statistics to be calculated. More...

Public Member Functions
	QgsDateTimeStatisticalSummary (const QgsDateTimeStatisticalSummary::Statistics &stats=All)
	Constructor for QgsDateTimeStatisticalSummary. More...
void	addValue (const QVariant &value)
	Adds a single datetime to the statistics calculation. More...
void	calculate (const QVariantList &values)
	Calculates summary statistics for a list of variants. More...
int	count () const
	Returns the calculated count of values. More...
int	countDistinct () const
	Returns the number of distinct datetime values. More...
int	countMissing () const
	Returns the number of missing (null) datetime values. More...
QSet< QDateTime >	distinctValues () const
	Returns the set of distinct datetime values. More...
void	finalize ()
	Must be called after adding all datetimes with addValue() and before retrieving any calculated datetime statistics. More...
QDateTime	max () const
	Returns the maximum (latest) non-null datetime value. More...
QDateTime	min () const
	Returns the minimum (earliest) non-null datetime value. More...
QgsInterval	range () const
	Returns the range (interval between earliest and latest non-null datetime values). More...
void	reset ()
	Resets the calculated values. More...
void	setStatistics (const Statistics &stats)
	Sets flags which specify which statistics will be calculated. More...
QVariant	statistic (Statistic stat) const
	Returns the value of a specified statistic. More...
Statistics	statistics () const
	Returns flags which specify which statistics will be calculated. More...

Static Public Member Functions
static QString	displayName (Statistic statistic)
	Returns the friendly display name for a statistic. More...

Detailed Description

Calculator for summary statistics and aggregates for a list of datetimes.

Statistics are calculated by calling calculate and passing a list of datetimes. The individual statistics can then be retrieved using the associated methods. Note that not all statistics are calculated by default. Statistics which require slower computations are only calculated by specifying the statistic in the constructor or via setStatistics.

Note

Added in version 2.16

Definition at line 43 of file qgsdatetimestatisticalsummary.h.

Member Enumeration Documentation

Statistic

enum QgsDateTimeStatisticalSummary::Statistic

Enumeration of flags that specify statistics to be calculated.

Enumerator
Count	Count.
CountDistinct	Number of distinct datetime values.
CountMissing	Number of missing (null) values.
Min	Minimum (earliest) datetime value.
Max	Maximum (latest) datetime value.
Range	Interval between earliest and latest datetime value.
All

Definition at line 48 of file qgsdatetimestatisticalsummary.h.

Constructor & Destructor Documentation

QgsDateTimeStatisticalSummary()

QgsDateTimeStatisticalSummary::QgsDateTimeStatisticalSummary

(

const QgsDateTimeStatisticalSummary::Statistics &

stats = All

)

Constructor for QgsDateTimeStatisticalSummary.

Parameters

stats

flags for statistics to calculate

Definition at line 31 of file qgsdatetimestatisticalsummary.cpp.

Member Function Documentation

addValue()

void QgsDateTimeStatisticalSummary::addValue

(

const QVariant &

value

)

Adds a single datetime to the statistics calculation.

Calling this method allows datetimes to be added to the calculation one at a time. For large quantities of dates this may be more efficient then first adding all the variants to a list and calling calculate().

Parameters

value

datetime to add. Any non-datetime variants will be ignored.

Note

call reset() before adding the first datetime using this method to clear the results from any previous calculations

finalize() must be called after adding the final value and before retrieving calculated statistics.

See also

calculate()

finalize()

Definition at line 57 of file qgsdatetimestatisticalsummary.cpp.

calculate()

void QgsDateTimeStatisticalSummary::calculate

(

const QVariantList &

values

)

Calculates summary statistics for a list of variants.

Any non-datetime variants will be ignored.

Parameters

values

list of variants

See also

addValue()

Definition at line 46 of file qgsdatetimestatisticalsummary.cpp.

count()

int QgsDateTimeStatisticalSummary::count ( ) const

inline

Returns the calculated count of values.

Definition at line 117 of file qgsdatetimestatisticalsummary.h.

countDistinct()

int QgsDateTimeStatisticalSummary::countDistinct ( ) const

inline

Returns the number of distinct datetime values.

Definition at line 121 of file qgsdatetimestatisticalsummary.h.

countMissing()

int QgsDateTimeStatisticalSummary::countMissing ( ) const

inline

Returns the number of missing (null) datetime values.

Definition at line 129 of file qgsdatetimestatisticalsummary.h.

displayName()

QString QgsDateTimeStatisticalSummary::displayName ( QgsDateTimeStatisticalSummary::Statistic  statistic )

static

Returns the friendly display name for a statistic.

Parameters

statistic

statistic to return name for

Definition at line 135 of file qgsdatetimestatisticalsummary.cpp.

distinctValues()

QSet< QDateTime > QgsDateTimeStatisticalSummary::distinctValues ( ) const

inline

Returns the set of distinct datetime values.

Definition at line 125 of file qgsdatetimestatisticalsummary.h.

finalize()

void QgsDateTimeStatisticalSummary::finalize

(

)

Must be called after adding all datetimes with addValue() and before retrieving any calculated datetime statistics.

See also

addValue()

Definition at line 72 of file qgsdatetimestatisticalsummary.cpp.

max()

QDateTime QgsDateTimeStatisticalSummary::max ( ) const

inline

Returns the maximum (latest) non-null datetime value.

Definition at line 137 of file qgsdatetimestatisticalsummary.h.

min()

QDateTime QgsDateTimeStatisticalSummary::min ( ) const

inline

Returns the minimum (earliest) non-null datetime value.

Definition at line 133 of file qgsdatetimestatisticalsummary.h.

range()

QgsInterval QgsDateTimeStatisticalSummary::range ( ) const

inline

Returns the range (interval between earliest and latest non-null datetime values).

Definition at line 141 of file qgsdatetimestatisticalsummary.h.

reset()

void QgsDateTimeStatisticalSummary::reset

(

)

Resets the calculated values.

Definition at line 37 of file qgsdatetimestatisticalsummary.cpp.

setStatistics()

void QgsDateTimeStatisticalSummary::setStatistics ( const Statistics &  stats )

inline

Sets flags which specify which statistics will be calculated.

Some statistics are always calculated (eg count).

Parameters

stats

flags for statistics to calculate

See also

statistics

Definition at line 76 of file qgsdatetimestatisticalsummary.h.

statistic()

QVariant QgsDateTimeStatisticalSummary::statistic

(

QgsDateTimeStatisticalSummary::Statistic

stat

)

const

Returns the value of a specified statistic.

Parameters

stat	statistic to return

Returns

calculated value of statistic

Definition at line 113 of file qgsdatetimestatisticalsummary.cpp.

statistics()

Statistics QgsDateTimeStatisticalSummary::statistics ( ) const

inline

Returns flags which specify which statistics will be calculated.

Some statistics are always calculated (eg count).

See also

setStatistics

Definition at line 69 of file qgsdatetimestatisticalsummary.h.

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The documentation for this class was generated from the following files:

• /tmp/buildd/qgis-2.18.21+99unstable/src/core/qgsdatetimestatisticalsummary.h
• /tmp/buildd/qgis-2.18.21+99unstable/src/core/qgsdatetimestatisticalsummary.cpp