Class: QgsAbstractPropertyCollection¶
- class qgis.core.QgsAbstractPropertyCollection(name: str = '')¶
Bases:
sip.wrapper
Constructor for
QgsAbstractPropertyCollection
. The name parameter should be set to a descriptive name for the collection.QgsAbstractPropertyCollection(
QgsAbstractPropertyCollection
)Abstract base class for
QgsPropertyCollection
like objects.New in version 3.0:
Methods
Removes all properties from the collection.
Returns
True
if the collection has any active properties, orFalse
if all properties within the collection are deactivated.Returns
True
if the collection has any active, non-static properties, orFalse
if either all non-static properties within the collection are deactivated or if the collection only contains static properties.Returns
True
if the collection contains a property with the specified key.Returns
True
if the collection contains an active property with the specified key.Loads this property collection from a QVariantMap, wrapped in a QVariant.
Returns the descriptive name of the property collection.
Prepares the collection against a specified expression context.
Returns a matching property from the collection, if one exists.
Returns a list of property keys contained within the collection.
Reads property collection state from an XML element.
Returns the set of any fields referenced by the active properties from the collection.
Sets the descriptive name for the property collection.
Saves this property collection to a QVariantMap, wrapped in a QVariant.
Returns the calculated value of the property with the specified key from within the collection.
Calculates the current value of the property with the specified key and interprets it as an boolean.
Calculates the current value of the property with the specified key and interprets it as a color.
Calculates the current value of the property with the specified key and interprets it as a datetime.
Calculates the current value of the property with the specified key and interprets it as a double.
Calculates the current value of the property with the specified key and interprets it as an integer.
Calculates the current value of the property with the specified key and interprets it as a string.
Writes the current state of the property collection into an XML element
- clear(self)¶
Removes all properties from the collection.
- hasActiveProperties(self) bool ¶
Returns
True
if the collection has any active properties, orFalse
if all properties within the collection are deactivated.See also
- Return type
bool
- hasDynamicProperties(self) bool ¶
Returns
True
if the collection has any active, non-static properties, orFalse
if either all non-static properties within the collection are deactivated or if the collection only contains static properties.See also
- Return type
bool
- hasProperty(self, key: int) bool ¶
Returns
True
if the collection contains a property with the specified key.- Parameters
key (int) – integer key for property. The intended use case is that a context specific enum is cast to int and used for the key value.
See also
- Return type
bool
- isActive(self, key: int) bool ¶
Returns
True
if the collection contains an active property with the specified key.- Parameters
key (int) – integer key for property to test. The intended use case is that a context specific enum is cast to int and used for the key value.
- Return type
bool
- loadVariant(self, configuration: Any, definitions: Dict[int, QgsPropertyDefinition]) bool ¶
Loads this property collection from a QVariantMap, wrapped in a QVariant. You can use QgsXmlUtils.readVariant to save it to an XML document.
See also
- Parameters
configuration (Any) –
definitions (Dict[int) –
- Return type
bool
- name(self) str ¶
Returns the descriptive name of the property collection.
See also
- Return type
str
- prepare(self, context: QgsExpressionContext = QgsExpressionContext()) bool ¶
Prepares the collection against a specified expression context. Calling prepare before evaluating the collection’s properties multiple times allows precalculation of expensive setup tasks such as parsing expressions. Returns
True
if preparation was successful.- Parameters
context (
QgsExpressionContext
= QgsExpressionContext()) –- Return type
bool
- property(self, key: int) QgsProperty ¶
Returns a matching property from the collection, if one exists.
- Parameters
key (int) – integer key for property to return. The intended use case is that a context specific enum is cast to int and used for the key value.
- Return type
- Returns
matching property, or null if no matching, active property found.
See also
- propertyKeys(self) object ¶
Returns a list of property keys contained within the collection.
- Return type
object
- readXml(self, collectionElem: QDomElement, definitions: Dict[int, QgsPropertyDefinition]) bool ¶
Reads property collection state from an XML element.
- Parameters
collectionElem (QDomElement) – source DOM element for property collection’s state
definitions (Dict[int) – property definitions
See also
- Return type
bool
- referencedFields(self, context: QgsExpressionContext = QgsExpressionContext(), ignoreContext: bool = False) Set[str] ¶
Returns the set of any fields referenced by the active properties from the collection.
- Parameters
context (
QgsExpressionContext
= QgsExpressionContext()) – expression context the properties will be evaluated against.ignoreContext (bool = False) – This parameter has been added in QGIS 3.14. When set to
True
, even fields not set in context’sfields()
will be reported - this is useful e.g. with vector tiles where the actual available field names may not be known beforehand.
- Return type
Set[str]
- setName(self, name: str)¶
Sets the descriptive name for the property collection.
See also
- Parameters
name (str) –
- toVariant(self, definitions: Dict[int, QgsPropertyDefinition]) Any ¶
Saves this property collection to a QVariantMap, wrapped in a QVariant. You can use QgsXmlUtils.writeVariant to save it to an XML document.
See also
- Parameters
definitions (Dict[int) –
- Return type
Any
- value(self, key: int, context: QgsExpressionContext, defaultValue: Any = None) Any ¶
Returns the calculated value of the property with the specified key from within the collection. If you need the validity of the value (like ok provided from the valueAs* variants) refer to the
property()
andQgsProperty.value()
- Parameters
key (int) – integer key for property to return. The intended use case is that a context specific enum is cast to int and used for the key value.
context (QgsExpressionContext) – expression context to evaluate property against
defaultValue (Any = None) – default value to return if no matching, active property found or if the property value cannot be calculated
- Return type
Any
- Returns
calculated property value, or default value if property could not be evaluated
See also
See also
See also
See also
See also
- valueAsBool(self, key: int, context: QgsExpressionContext, defaultValue: bool = False) Tuple[bool, bool] ¶
Calculates the current value of the property with the specified key and interprets it as an boolean.
- Parameters
key (int) – integer key for property to return. The intended use case is that a context specific enum is cast to int and used for the key value.
context (QgsExpressionContext) –
QgsExpressionContext
to evaluate the property for.defaultValue (bool = False) – default boolean to return if the property cannot be calculated as a boolean
- Return type
Tuple[bool, bool]
- Returns
value parsed to bool
ok: will be set to
True
if conversion was successful
See also
See also
See also
See also
See also
See also
- valueAsColor(self, key: int, context: QgsExpressionContext, defaultColor: Union[QColor, Qt.GlobalColor, QGradient] = QColor()) Tuple[QColor, bool] ¶
Calculates the current value of the property with the specified key and interprets it as a color.
- Parameters
key (int) – integer key for property to return. The intended use case is that a context specific enum is cast to int and used for the key value.
context (QgsExpressionContext) –
QgsExpressionContext
to evaluate the property for.defaultColor (Union[QColor) – default color to return if the property cannot be calculated as a color
- Return type
Tuple[QColor, bool]
- Returns
value parsed to color
ok: will be set to
True
if conversion was successful
See also
See also
See also
See also
See also
See also
- valueAsDateTime(self, key: int, context: QgsExpressionContext, defaultDateTime: Union[QDateTime, datetime.datetime] = QDateTime()) Tuple[QDateTime, bool] ¶
Calculates the current value of the property with the specified key and interprets it as a datetime.
- Parameters
key (int) – integer key for property to return. The intended use case is that a context specific enum is cast to int and used for the key value.
context (QgsExpressionContext) –
QgsExpressionContext
to evaluate the property for.defaultDateTime (Union[QDateTime) – default datetime to return if the property cannot be calculated as a datetime
- Return type
Tuple[QDateTime, bool]
- Returns
value parsed to datetime
ok: will be set to
True
if conversion was successful
See also
See also
See also
See also
See also
See also
New in version 3.14.
- valueAsDouble(self, key: int, context: QgsExpressionContext, defaultValue: float = 0) Tuple[float, bool] ¶
Calculates the current value of the property with the specified key and interprets it as a double.
- Parameters
key (int) – integer key for property to return. The intended use case is that a context specific enum is cast to int and used for the key value.
context (QgsExpressionContext) –
QgsExpressionContext
to evaluate the property for.defaultValue (float = 0) – default double to return if the property cannot be calculated as a double
- Return type
Tuple[float, bool]
- Returns
value parsed to double
ok: will be set to
True
if conversion was successful
See also
See also
See also
See also
See also
See also
- valueAsInt(self, key: int, context: QgsExpressionContext, defaultValue: int = 0) Tuple[int, bool] ¶
Calculates the current value of the property with the specified key and interprets it as an integer.
- Parameters
key (int) – integer key for property to return. The intended use case is that a context specific enum is cast to int and used for the key value.
context (QgsExpressionContext) –
QgsExpressionContext
to evaluate the property for.defaultValue (int = 0) – default integer to return if the property cannot be calculated as a integer
- Return type
Tuple[int, bool]
- Returns
value parsed to integer
ok: will be set to
True
if conversion was successful
See also
See also
See also
See also
See also
See also
- valueAsString(self, key: int, context: QgsExpressionContext, defaultString: str = '') Tuple[str, bool] ¶
Calculates the current value of the property with the specified key and interprets it as a string.
- Parameters
key (int) – integer key for property to return. The intended use case is that a context specific enum is cast to int and used for the key value.
context (QgsExpressionContext) –
QgsExpressionContext
to evaluate the property for.defaultString (str = '') – default string to return if the property cannot be calculated as a string
- Return type
Tuple[str, bool]
- Returns
value parsed to string
ok: will be set to
True
if conversion was successful
See also
See also
See also
See also
See also
See also
- writeXml(self, collectionElem: QDomElement, definitions: Dict[int, QgsPropertyDefinition]) bool ¶
Writes the current state of the property collection into an XML element
- Parameters
collectionElem (QDomElement) – destination element for the property collection’s state
definitions (Dict[int) – property definitions
See also
- Return type
bool