Class: QgsAbstractPropertyCollection¶
- class qgis.core.QgsAbstractPropertyCollection¶
Bases:
sip.wrapper
Abstract base class for
QgsPropertyCollection
like objects.New in version 3.0.
QgsAbstractPropertyCollection(name: str = ‘’) Constructor for
QgsAbstractPropertyCollection
. The name parameter should be set to a descriptive name for the collection.QgsAbstractPropertyCollection(
QgsAbstractPropertyCollection
)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
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- 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
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- valueAsColor(self, key: int, context: QgsExpressionContext, defaultColor: 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
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- valueAsDateTime(self, key: int, context: QgsExpressionContext, defaultDateTime: 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
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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
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- 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
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- 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
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- 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