Class: QgsExpressionNodeIndexOperator

An indexing expression operator, which allows use of square brackets [] to reference map and array items.

Added in version 3.6.

Class Hierarchy

Base classes

QgsExpressionNode

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

class qgis.core.QgsExpressionNodeIndexOperator

Bases: QgsExpressionNode

__init__(container: QgsExpressionNode | None, index: QgsExpressionNode | None)

Constructor for QgsExpressionNodeIndexOperator.

Parameters:

• container (Optional[QgsExpressionNode])

• index (Optional[QgsExpressionNode])

container(self) → QgsExpressionNode | None

Returns the container node, representing an array or map value.

See also

index()

Return type:

Optional[QgsExpressionNode]

virtual evalNode(self, parent: QgsExpression | None, context: QgsExpressionContext | None) → Any

Parameters:

• parent (Optional[QgsExpression])

• context (Optional[QgsExpressionContext])

Return type:

Any

index(self) → QgsExpressionNode | None

Returns the index node, representing an array element index or map key.

See also

container()

Return type:

Optional[QgsExpressionNode]

virtual prepareNode(self, parent: QgsExpression | None, context: QgsExpressionContext | None) → bool

Parameters:

• parent (Optional[QgsExpression])

• context (Optional[QgsExpressionContext])

Return type:

bool