Class: QgsProcessingParameterString

class qgis.core.QgsProcessingParameterString

Bases: QgsProcessingParameterDefinition

A string parameter for processing algorithms.

A parameter type which allows users to enter any string value.

In some circumstances it is desirable to restrict the values available when a user is asked to enter a string parameter to a list of predetermined “valid” values. Since QGIS 3.22 this can be done by setting the widget wrapper metadata “value_hints” option, as demonstrated below. (While this provides a mechanism for guiding users to select from valid string values when running a Processing algorithm through the GUI, it does not place any limits on the string values accepted via PyQGIS codes or when running the algorithm via other non-gui means. Algorithms should gracefully handle other values accordingly.)

param = QgsProcessingParameterString( 'PRINTER_NAME', 'Printer name')
# show only printers which are available on the current system as options
# for the string input.
param.setMetadata( {'widget_wrapper':
  { 'value_hints': ['Inkjet printer', 'Laser printer'] }
})

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

QgsProcessingParameterString(QgsProcessingParameterString)

Methods

asPythonString

param outputType:

asScriptCode

rtype:

str

clone

rtype:

QgsProcessingParameterDefinition

defaultGuiValueFromSetting

Default gui value for an algorithm parameter from settings

fromScriptCode

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

fromVariantMap

param map:

multiLine

Returns True if the parameter allows multiline strings.

setMultiLine

Sets whether the parameter allows multiline strings.

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.PythonOutputType.PythonQgsProcessingAlgorithmSubclass) str
Parameters:

outputType (QgsProcessing.PythonOutputType = QgsProcessing.PythonOutputType.PythonQgsProcessingAlgorithmSubclass) –

Return type:

str

asScriptCode(self) str
Return type:

str

clone(self) QgsProcessingParameterDefinition
Return type:

QgsProcessingParameterDefinition

defaultGuiValueFromSetting(self) Any

Default gui value for an algorithm parameter from settings

Returns:

default value from settings or invalid QVariant if there is no default value defined in the settings

New in version 3.34.

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

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

Parameters:
  • name (str) –

  • description (str) –

  • isOptional (bool) –

  • definition (str) –

Return type:

QgsProcessingParameterString

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

map (Dict[str) –

Return type:

bool

multiLine(self) bool

Returns True if the parameter allows multiline strings.

See also

setMultiLine()

Return type:

bool

setMultiLine(self, multiLine: bool)

Sets whether the parameter allows multiline strings.

See also

multiLine()

Parameters:

multiLine (bool) –

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