Class: QgsExpressionNodeFunction

An expression node for expression functions.

List of all members, including inherited members

Class Hierarchy

Inheritance diagram of qgis.core.QgsExpressionNodeFunction

Base classes

QgsExpressionNode

Abstract base class for all nodes that can appear in an expression.

Methods

args

Returns a list of arguments specified for the function.

fnIndex

Returns the index of the node's function.

Virtual Methods

In PyQGIS, only methods marked as virtual can be safely overridden in a Python subclass of QgsExpressionNodeFunction. See the FAQ for more details.

evalNode

prepareNode

Static Methods

validateParams

Tests whether the provided argument list is valid for the matching function
class qgis.core.QgsExpressionNodeFunction[source]

Bases: QgsExpressionNode

__init__(fnIndex: int, args: QgsExpressionNode.NodeList | None)

A function node consists of an index of the function in the global function array and a list of arguments that will be passed to it.

Parameters:
args(self) → QgsExpressionNode.NodeList | None[source]

Returns a list of arguments specified for the function.

Return type:

Optional[QgsExpressionNode.NodeList]

virtual evalNode(self, parent: QgsExpression | None, context: QgsExpressionContext | None) → Any[source]
Parameters:
Return type:

Any

fnIndex(self) → int[source]

Returns the index of the node’s function.

Return type:

int

virtual prepareNode(self, parent: QgsExpression | None, context: QgsExpressionContext | None) → bool[source]
Parameters:
Return type:

bool

static validateParams(fnIndex: int, args: QgsExpressionNode.NodeList | None, error: str | None) → bool[source]

Tests whether the provided argument list is valid for the matching function

Parameters:
Return type:

bool