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

#include <qgsstringstatisticalsummary.h>

Public Types
enum	Statistic { Count = 1, CountDistinct = 2, CountMissing = 4, Min = 8, Max = 16, MinimumLength = 32, MaximumLength = 64, MeanLength = 128, All = Count \| CountDistinct \| CountMissing \| Min \| Max \| MinimumLength \| MaximumLength \| MeanLength }
	Enumeration of flags that specify statistics to be calculated. More...

Public Member Functions
	QgsStringStatisticalSummary (QgsStringStatisticalSummary::Statistics stats=QgsStringStatisticalSummary::All)
	Constructor for QgsStringStatistics. More...

void	addString (const QString &string)
	Adds a single string to the statistics calculation. More...

void	addValue (const QVariant &value)
	Adds a single variant to the statistics calculation. More...

void	calculate (const QStringList &values)
	Calculates summary statistics for an entire list of strings at once. More...

void	calculateFromVariants (const QVariantList &values)
	Calculates summary statistics for an entire list of variants at once. More...

int	count () const
	Returns the calculated count of values. More...

int	countDistinct () const
	Returns the number of distinct string values. More...

int	countMissing () const
	Returns the number of missing (null) string values. More...

QSet< QString >	distinctValues () const
	Returns the set of distinct string values. More...

void	finalize ()
	Must be called after adding all strings with addString() and before retrieving any calculated string statistics. More...

QString	max () const
	Returns the maximum (non-null) string value. More...

int	maxLength () const
	Returns the maximum length of strings. More...

double	meanLength () const
	Returns the mean length of strings. More...

QString	min () const
	Returns the minimum (non-null) string value. More...

int	minLength () const
	Returns the minimum length of strings. More...

void	reset ()
	Resets the calculated values. More...

void	setStatistics (QgsStringStatisticalSummary::Statistics stats)
	Sets flags which specify which statistics will be calculated. More...

QVariant	statistic (QgsStringStatisticalSummary::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 (QgsStringStatisticalSummary::Statistic statistic)
	Returns the friendly display name for a statistic. More...

Detailed Description

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

Statistics are calculated by calling calculate() and passing a list of strings. 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().

Since: QGIS 2.16

Definition at line 43 of file qgsstringstatisticalsummary.h.

Member Enumeration Documentation

◆ Statistic

enum QgsStringStatisticalSummary::Statistic

Enumeration of flags that specify statistics to be calculated.

Enumerator
Count	Count.
CountDistinct	Number of distinct string values.
CountMissing	Number of missing (null) values.
Min	Minimum string value.
Max	Maximum string value.
MinimumLength	Minimum length of string.
MaximumLength	Maximum length of string.
MeanLength	Mean length of strings.
All

Definition at line 48 of file qgsstringstatisticalsummary.h.

Constructor & Destructor Documentation

◆ QgsStringStatisticalSummary()

QgsStringStatisticalSummary::QgsStringStatisticalSummary ( QgsStringStatisticalSummary::Statistics stats = QgsStringStatisticalSummary::All )

Constructor for QgsStringStatistics.

Parameters

stats flags for statistics to calculate

Definition at line 30 of file qgsstringstatisticalsummary.cpp.

Member Function Documentation

◆ addString()

void QgsStringStatisticalSummary::addString ( const QString & string )

Adds a single string to the statistics calculation.

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

Parameters

string string to add

Note: call reset() before adding the first string using this method to clear the results from any previous calculations; finalize() must be called after adding the final string and before retrieving calculated statistics.

See also: calculate(); addValue(); finalize()

Definition at line 60 of file qgsstringstatisticalsummary.cpp.

◆ addValue()

void QgsStringStatisticalSummary::addValue ( const QVariant & value )

Adds a single variant to the statistics calculation.

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

Parameters

value variant to add

Note: call reset() before adding the first string 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: calculateFromVariants(); finalize()

Definition at line 65 of file qgsstringstatisticalsummary.cpp.

◆ calculate()

void QgsStringStatisticalSummary::calculate ( const QStringList & values )

Calculates summary statistics for an entire list of strings at once.

Parameters

values list of strings

See also: calculateFromVariants(); addString()

Definition at line 49 of file qgsstringstatisticalsummary.cpp.

◆ calculateFromVariants()

void QgsStringStatisticalSummary::calculateFromVariants ( const QVariantList & values )

Calculates summary statistics for an entire list of variants at once.

Any non-string variants will be ignored.

Parameters

values list of variants

See also: calculate(); addValue()

Definition at line 79 of file qgsstringstatisticalsummary.cpp.

◆ count()

int QgsStringStatisticalSummary::count ( ) const

inline

Returns the calculated count of values.

Definition at line 153 of file qgsstringstatisticalsummary.h.

◆ countDistinct()

int QgsStringStatisticalSummary::countDistinct ( ) const

inline

Returns the number of distinct string values.

See also: distinctValues()

Definition at line 159 of file qgsstringstatisticalsummary.h.

◆ countMissing()

int QgsStringStatisticalSummary::countMissing ( ) const

inline

Returns the number of missing (null) string values.

Definition at line 170 of file qgsstringstatisticalsummary.h.

◆ displayName()

QString QgsStringStatisticalSummary::displayName ( QgsStringStatisticalSummary::Statistic statistic )

static

Returns the friendly display name for a statistic.

Parameters

statistic statistic to return name for

Definition at line 157 of file qgsstringstatisticalsummary.cpp.

◆ distinctValues()

QSet< QString > QgsStringStatisticalSummary::distinctValues ( ) const

inline

Returns the set of distinct string values.

See also: countDistinct()

Definition at line 165 of file qgsstringstatisticalsummary.h.

◆ finalize()

void QgsStringStatisticalSummary::finalize ( )

Must be called after adding all strings with addString() and before retrieving any calculated string statistics.

See also: addString()

Definition at line 74 of file qgsstringstatisticalsummary.cpp.

◆ max()

QString QgsStringStatisticalSummary::max ( ) const

inline

Returns the maximum (non-null) string value.

Definition at line 180 of file qgsstringstatisticalsummary.h.

◆ maxLength()

int QgsStringStatisticalSummary::maxLength ( ) const

inline

Returns the maximum length of strings.

Definition at line 190 of file qgsstringstatisticalsummary.h.

◆ meanLength()

double QgsStringStatisticalSummary::meanLength ( ) const

inline

Returns the mean length of strings.

Since: QGIS 3.0

Definition at line 196 of file qgsstringstatisticalsummary.h.

◆ min()

QString QgsStringStatisticalSummary::min ( ) const

inline

Returns the minimum (non-null) string value.

Definition at line 175 of file qgsstringstatisticalsummary.h.

◆ minLength()

int QgsStringStatisticalSummary::minLength ( ) const

inline

Returns the minimum length of strings.

Definition at line 185 of file qgsstringstatisticalsummary.h.

◆ reset()

void QgsStringStatisticalSummary::reset ( )

Resets the calculated values.

Definition at line 36 of file qgsstringstatisticalsummary.cpp.

◆ setStatistics()

void QgsStringStatisticalSummary::setStatistics ( QgsStringStatisticalSummary::Statistics stats )

inline

Sets flags which specify which statistics will be calculated.

Some statistics are always calculated (e.g., count).

Parameters

stats flags for statistics to calculate

See also: statistics

Definition at line 81 of file qgsstringstatisticalsummary.h.

◆ statistic()

QVariant QgsStringStatisticalSummary::statistic ( QgsStringStatisticalSummary::Statistic stat ) const

Returns the value of a specified statistic.

Parameters

stat	statistic to return

Returns: calculated value of statistic

Definition at line 131 of file qgsstringstatisticalsummary.cpp.

◆ statistics()

Statistics QgsStringStatisticalSummary::statistics ( ) const

inline

Returns flags which specify which statistics will be calculated.

Some statistics are always calculated (e.g., count).

See also: setStatistics

Definition at line 73 of file qgsstringstatisticalsummary.h.

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

/tmp/buildd/qgis-3.6.0+99unstable/src/core/qgsstringstatisticalsummary.h
/tmp/buildd/qgis-3.6.0+99unstable/src/core/qgsstringstatisticalsummary.cpp

Public Types

Public Member Functions

Static Public Member Functions

Detailed Description

Member Enumeration Documentation

◆ Statistic

Constructor & Destructor Documentation

◆ QgsStringStatisticalSummary()

Member Function Documentation

◆ addString()

◆ addValue()

◆ calculate()

◆ calculateFromVariants()

◆ count()

◆ countDistinct()

◆ countMissing()

◆ displayName()

◆ distinctValues()

◆ finalize()

◆ max()

◆ maxLength()

◆ meanLength()

◆ min()

◆ minLength()

◆ reset()

◆ setStatistics()

◆ statistic()

◆ statistics()