Class: QgsExpressionNodeUnaryOperator

A unary node is either negative as in boolean (not) or as in numbers (minus).

Note

This is an abstract class, with methods which must be implemented by a subclass.

The following methods must be implemented: QgsExpressionNode.needsGeometry()

Class Hierarchy

Base classes

QgsExpressionNode

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

class qgis.core.QgsExpressionNodeUnaryOperator

Bases: QgsExpressionNode

__init__(op: QgsExpressionNodeUnaryOperator.UnaryOperator, operand: QgsExpressionNode | None)

A node unary operator is modifying the value of operand by negating it with op.

Parameters:

• op (QgsExpressionNodeUnaryOperator.UnaryOperator)

• operand (Optional[QgsExpressionNode])

class UnaryOperator

Bases: int

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

Parameters:

• parent (Optional[QgsExpression])

• context (Optional[QgsExpressionContext])

Return type:

Any

op(self) → QgsExpressionNodeUnaryOperator.UnaryOperator

Returns the unary operator.

Return type:

QgsExpressionNodeUnaryOperator.UnaryOperator

operand(self) → QgsExpressionNode | None

Returns the node the operator will operate upon.

Return type:

Optional[QgsExpressionNode]

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

Parameters:

• parent (Optional[QgsExpression])

• context (Optional[QgsExpressionContext])

Return type:

bool

text(self) → str

Returns a the name of this operator without the operands. I.e. “NOT” or “-”

Return type:

str

uoMinus = 1

uoNot = 0