QgsDateTimeStatisticalSummary class

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

Contents

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().

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.

Public static functions

static auto displayName(QgsDateTimeStatisticalSummary::Statistic statistic) -> QString
Returns the friendly display name for a statistic.

Constructors, destructors, conversion operators

QgsDateTimeStatisticalSummary(QgsDateTimeStatisticalSummary::Statistics stats = All)
Constructor for QgsDateTimeStatisticalSummary.

Public functions

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

Enum documentation

enum QgsDateTimeStatisticalSummary::Statistic

Enumeration of flags that specify statistics to be calculated.

Enumerators
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

Function documentation

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

Returns the friendly display name for a statistic.

Parameters
statistic statistic to return name for

QgsDateTimeStatisticalSummary::QgsDateTimeStatisticalSummary(QgsDateTimeStatisticalSummary::Statistics stats = All)

Constructor for QgsDateTimeStatisticalSummary.

Parameters
stats flags for statistics to calculate

void QgsDateTimeStatisticalSummary::addValue(const QVariant& value)

Adds a single datetime to the statistics calculation.

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

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().

void QgsDateTimeStatisticalSummary::calculate(const QVariantList& values)

Calculates summary statistics for a list of variants.

Parameters
values list of variants

Any non-datetime variants will be ignored.

void QgsDateTimeStatisticalSummary::finalize()

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

void QgsDateTimeStatisticalSummary::setStatistics(Statistics stats)

Sets flags which specify which statistics will be calculated.

Parameters
stats flags for statistics to calculate

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

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

Returns the value of a specified statistic.

Parameters
stat statistic to return
Returns calculated value of statistic

Statistics QgsDateTimeStatisticalSummary::statistics() const

Returns flags which specify which statistics will be calculated.

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