Subgroup: Processing

Class: QgsProcessingParameterExpression¶

class qgis.core.QgsProcessingParameterExpression¶

Bases: qgis._core.QgsProcessingParameterDefinition

An expression parameter for processing algorithms.

New in version 3.0: Methods

`algorithm`	Returns a pointer to the algorithm which owns this parameter.
`asScriptCode`	Returns the parameter definition encoded in a string which can be used within a Python processing script.
`checkValueIsAcceptable`	Checks whether the specified `input` value is acceptable for the parameter.
`clone`
`defaultValue`	Returns the default value for the parameter.
`dependsOnOtherParameters`
`description`	Returns the description for the parameter.
`dynamicLayerParameterName`	Returns the name of the parameter for a layer linked to a dynamic parameter, or an empty string if this is not set.
`dynamicPropertyDefinition`	Returns the property definition for dynamic properties.
`flags`	Returns any flags associated with the parameter.
`fromScriptCode`	Creates a new parameter using the definition from a script code.
`fromVariantMap`
`isDestination`	Returns true if this parameter represents a file or layer destination, e.g.
`isDynamic`	Returns true if the parameter supports is dynamic, and can support data-defined values (i.e.
`metadata`	Returns the parameter’s freeform metadata.
`name`	Returns the name of the parameter.
`parentLayerParameterName`	Returns the name of the parent layer parameter, or an empty string if this is not set.
`provider`	Returns a pointer to the provider for the algorithm which owns this parameter.
`setDefaultValue`	Sets the default `value` for the parameter.
`setDescription`	Sets the `description` for the parameter.
`setDynamicLayerParameterName`	Sets the `name` for the parameter for a layer linked to a dynamic parameter, or an empty string if this is not set.
`setDynamicPropertyDefinition`	Sets the property `definition` for dynamic properties.
`setFlags`	Sets the `flags` associated with the parameter.
`setIsDynamic`	Sets whether the parameter is `dynamic`, and can support data-defined values (i.e.
`setMetadata`	Sets the parameter’s freeform `metadata`.
`setName`	Sets the `name` of the parameter.
`setParentLayerParameterName`	Sets the name of the parent layer parameter.
`toVariantMap`
`toolTip`	Returns a formatted tooltip for use with the parameter, which gives helpful information like parameter description, ID, and extra content like default values (depending on parameter type).
`type`
`typeName`	Returns the type name for the parameter class.
`valueAsPythonString`

Attributes

`FlagAdvanced`
`FlagHidden`
`FlagOptional`

clone(self) → QgsProcessingParameterDefinition¶

dependsOnOtherParameters(self) → List[str]¶

fromScriptCode(name: str, description: str, isOptional: bool, definition: str) → QgsProcessingParameterExpression¶: Creates a new parameter using the definition from a script code.

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

parentLayerParameterName(self) → str¶: Returns the name of the parent layer parameter, or an empty string if this is not set.

See also

setParentLayerParameterName()

setParentLayerParameterName(self, parentLayerParameterName: str)¶: Sets the name of the parent layer parameter. Use an empty string if this is not required.

See also

parentLayerParameterName()

toVariantMap(self) → Dict[str, Any]¶

type(self) → str¶

typeName() → str¶: Returns the type name for the parameter class.

valueAsPythonString(self, value: Any, context: QgsProcessingContext) → str¶