Class: QgsProcessingParameterExpression

class qgis.core.QgsProcessingParameterExpression

Bases: QgsProcessingParameterDefinition

An expression parameter for processing algorithms.

New in version 3.0.

QgsProcessingParameterExpression(name: str, description: str = ‘’, defaultValue: Any = None, parentLayerParameterName: str = ‘’, optional: bool = False) Constructor for QgsProcessingParameterExpression.

QgsProcessingParameterExpression(QgsProcessingParameterExpression)

Methods

asPythonString

param outputType

clone

rtype

QgsProcessingParameterDefinition

dependsOnOtherParameters

rtype

List[str]

fromScriptCode

Creates a new parameter using the definition from a script code.

fromVariantMap

param map

parentLayerParameterName

Returns the name of the parent layer parameter, or an empty string if this is not set.

setParentLayerParameterName

Sets the name of the parent layer parameter.

toVariantMap

rtype

Dict[str, Any]

type

rtype

str

typeName

Returns the type name for the parameter class.

valueAsPythonString

param value

asPythonString(self, outputType: QgsProcessing.PythonOutputType = QgsProcessing.PythonQgsProcessingAlgorithmSubclass)str
Parameters

outputType (QgsProcessing.PythonOutputType = QgsProcessing.PythonQgsProcessingAlgorithmSubclass) –

Return type

str

clone(self)QgsProcessingParameterDefinition
Return type

QgsProcessingParameterDefinition

dependsOnOtherParameters(self)List[str]
Return type

List[str]

fromScriptCode(name: str, description: str, isOptional: bool, definition: str)QgsProcessingParameterExpression

Creates a new parameter using the definition from a script code.

Parameters
  • name (str) –

  • description (str) –

  • isOptional (bool) –

  • definition (str) –

Return type

QgsProcessingParameterExpression

fromVariantMap(self, map: Dict[str, Any])bool
Parameters

map (Dict[str) –

Return type

bool

parentLayerParameterName(self)str

Returns the name of the parent layer parameter, or an empty string if this is not set.

Return type

str

setParentLayerParameterName(self, parentLayerParameterName: str)

Sets the name of the parent layer parameter. Use an empty string if this is not required.

Parameters

parentLayerParameterName (str) –

toVariantMap(self)Dict[str, Any]
Return type

Dict[str, Any]

type(self)str
Return type

str

typeName()str

Returns the type name for the parameter class.

Return type

str

valueAsPythonString(self, value: Any, context: QgsProcessingContext)str
Parameters
Return type

str