Class: QgsProcessingParameterExpression

An expression parameter for processing algorithms.

Class Hierarchy

Base classes

QgsProcessingParameterDefinition

Base class for the definition of processing parameters.

class qgis.core.QgsProcessingParameterExpression

Bases: QgsProcessingParameterDefinition

__init__(name: str | None, description: str | None = '', defaultValue: Any = None, parentLayerParameterName: str | None = '', optional: bool = False, type: Qgis.ExpressionType = Qgis.ExpressionType.Qgis)

Constructor for QgsProcessingParameterExpression.

Parameters:

• name (Optional[str])

• description (Optional[str] = '')

• defaultValue (Any = None)

• parentLayerParameterName (Optional[str] = '')

• optional (bool = False)

• type (Qgis.ExpressionType = Qgis.ExpressionType.Qgis)

__init__(a0: QgsProcessingParameterExpression)

Parameters:

a0 (QgsProcessingParameterExpression)

expressionType(self) → Qgis.ExpressionType

Returns the parameter’s expression type.

See also

setExpressionType()

Added in version 3.32.

Return type:

Qgis.ExpressionType

static fromScriptCode(name: str | None, description: str | None, isOptional: bool, definition: str | None) → QgsProcessingParameterExpression | None

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

Parameters:

• name (Optional[str])

• description (Optional[str])

• isOptional (bool)

• definition (Optional[str])

Return type:

Optional[QgsProcessingParameterExpression]

parentLayerParameterName(self) → str

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

See also

setParentLayerParameterName()

Return type:

str

setExpressionType(self, type: Qgis.ExpressionType)

Sets the parameter’s expression type.

See also

expressionType()

Added in version 3.32.

Parameters:

type (Qgis.ExpressionType)

setParentLayerParameterName(self, parentLayerParameterName: str | None)

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

See also

parentLayerParameterName()

Parameters:

parentLayerParameterName (Optional[str])

static typeName() → str

Returns the type name for the parameter class.

Return type:

str