Class: QgsProcessingModelChildParameterSource

class qgis.core.QgsProcessingModelChildParameterSource

Bases: sip.wrapper

Constructor for QgsProcessingModelChildParameterSource. It is recommended that the static methods fromStaticValue(), fromModelParameter(), fromChildOutput() and fromExpression() are used instead.

QgsProcessingModelChildParameterSource(QgsProcessingModelChildParameterSource)

Source for the value of a parameter for a child algorithm within a model.

Methods

asPythonCode

Attempts to convert the source to executable Python code.

expression

Returns the source’s expression.

expressionText

Returns the source’s text with expressions.

fromChildOutput

Returns a new QgsProcessingModelChildParameterSource which takes its value from an output generated by a child algorithm.

fromExpression

Returns a new QgsProcessingModelChildParameterSource which takes its value from an expression.

fromExpressionText

Returns a new QgsProcessingModelChildParameterSource which takes its value from a text with expressions.

fromModelParameter

Returns a new QgsProcessingModelChildParameterSource which takes its value from a parent model parameter.

fromStaticValue

Returns a new QgsProcessingModelChildParameterSource which takes its value from a static value.

loadVariant

Loads this source from a QVariantMap.

outputChildId

Returns the source’s child algorithm ID from which the output value will be taken.

outputName

Returns the source’s child algorithm output name from which the output value will be taken.

parameterName

Returns the source’s model parameter name.

setExpression

Sets the source’s expression.

setExpressionText

Sets the source’s text containing expressions.

setOutputChildId

Sets the source’s child algorithm id from which the output value will be taken.

setOutputName

Sets the source’s child algorithm output name from which the output value will be taken.

setParameterName

Sets the source’s model parameter name.

setStaticValue

Sets the source’s static value.

source

Returns the parameter value’s source.

staticValue

Returns the source’s static value.

toVariant

Saves this source to a QVariant.

Attributes

ChildOutput

Expression

ExpressionText

ModelParameter

StaticValue

ChildOutput = 1
Expression = 3
ExpressionText = 4
ModelParameter = 0
class Source

Bases: int

StaticValue = 2
asPythonCode(self, outputType: QgsProcessing.PythonOutputType, definition: QgsProcessingParameterDefinition, friendlydChildNames: Dict[str, str]) → str

Attempts to convert the source to executable Python code.

The friendlyChildNames argument gives a map of child id to a friendly algorithm name, to be used in the code to identify that algorithm instead of the raw child id.

Parameters
Return type

str

expression(self) → str

Returns the source’s expression. This is only used when the source() is Expression.

See also

setExpression()

Return type

str

expressionText(self) → str

Returns the source’s text with expressions. This is only used when the source() is ExpressionText.

New in version 3.2.

Return type

str

fromChildOutput(childId: str, outputName: str) → QgsProcessingModelChildParameterSource

Returns a new QgsProcessingModelChildParameterSource which takes its value from an output generated by a child algorithm.

See also

fromExpression()

Parameters
  • childId (str) –

  • outputName (str) –

Return type

QgsProcessingModelChildParameterSource

fromExpression(expression: str) → QgsProcessingModelChildParameterSource

Returns a new QgsProcessingModelChildParameterSource which takes its value from an expression. The expression is evaluated just before the child algorithm executes, and can use functions available in its expression context to include results calculated from the child algorithms already executed by the model.

New in version 3.2.

Parameters

expression (str) –

Return type

QgsProcessingModelChildParameterSource

fromExpressionText(text: str) → QgsProcessingModelChildParameterSource

Returns a new QgsProcessingModelChildParameterSource which takes its value from a text with expressions. Expressions are evaluated just before the child algorithm executes, and can use functions available in its expression context to include results calculated from the child algorithms already executed by the model.

See also

fromExpression()

New in version 3.2.

Parameters

text (str) –

Return type

QgsProcessingModelChildParameterSource

fromModelParameter(parameterName: str) → QgsProcessingModelChildParameterSource

Returns a new QgsProcessingModelChildParameterSource which takes its value from a parent model parameter.

See also

fromExpression()

Parameters

parameterName (str) –

Return type

QgsProcessingModelChildParameterSource

fromStaticValue(value: Any) → QgsProcessingModelChildParameterSource

Returns a new QgsProcessingModelChildParameterSource which takes its value from a static value.

See also

fromExpression()

Parameters

value (Any) –

Return type

QgsProcessingModelChildParameterSource

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

Loads this source from a QVariantMap.

See also

toVariant()

Parameters

map (Dict[str) –

Return type

bool

outputChildId(self) → str

Returns the source’s child algorithm ID from which the output value will be taken. This is only used when the source() is ChildOutput.

See also

outputName()

Return type

str

outputName(self) → str

Returns the source’s child algorithm output name from which the output value will be taken. This is only used when the source() is ChildOutput.

See also

setOutputName()

See also

outputChildId()

Return type

str

parameterName(self) → str

Returns the source’s model parameter name. This is only used when the source() is ModelParameter.

Return type

str

setExpression(self, expression: str)

Sets the source’s expression. Calling this will also change the source() to Expression. The expression is evaluated just before the child algorithm executes, and can use functions available in its expression context to include results calculated from the child algorithms already executed by the model.

See also

expression()

Parameters

expression (str) –

setExpressionText(self, text: str)

Sets the source’s text containing expressions. Calling this will also change the source() to ExpressionText. Expressions are evaluated just before the child algorithm executes, and can use functions available in its expression context to include results calculated from the child algorithms already executed by the model.

See also

expressionText()

New in version 3.2.

Parameters

text (str) –

setOutputChildId(self, id: str)

Sets the source’s child algorithm id from which the output value will be taken. Calling this will also change the source() to ChildOutput.

See also

parameterName()

See also

setOutputName()

Parameters

id (str) –

setOutputName(self, name: str)

Sets the source’s child algorithm output name from which the output value will be taken. Calling this will also change the source() to ChildOutput.

See also

outputName()

Parameters

name (str) –

setParameterName(self, name: str)

Sets the source’s model parameter name. Calling this will also change the source() to ModelParameter.

See also

parameterName()

Parameters

name (str) –

setStaticValue(self, value: Any)

Sets the source’s static value. Calling this will also change the source() to StaticValue.

See also

staticValue()

Parameters

value (Any) –

source(self) → QgsProcessingModelChildParameterSource.Source

Returns the parameter value’s source.

Return type

QgsProcessingModelChildParameterSource.Source

staticValue(self) → Any

Returns the source’s static value. This is only used when the source() is StaticValue.

See also

setStaticValue()

Return type

Any

toVariant(self) → Any

Saves this source to a QVariant.

See also

loadVariant()

Return type

Any