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.

Methods

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

Virtual Methods

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

evalNode
prepareNode

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