Arrow expressions

Expressions are used to define filter logic for passing to a Dataset Scanner. FieldExpressions refer to columns in the Dataset and are compared to ScalarExpressions using ComparisonExpressions. ComparisonExpressions may be combined with AndExpression or OrExpression and negated with NotExpression.

Factory

FieldExpression$create(name) takes a string name as input. This string should refer to a column in a Dataset at the time it is evaluated, but you can construct a FieldExpression independently of any Dataset.

ScalarExpression$create(x) takes a scalar (length-1) R value as input.

ComparisonExpression$create(OP, e1, e2) takes a string operator name (e.g. "==", "!=", ">", etc.) and two Expression objects.

AndExpression$create(e1, e2) and OrExpression$create(e1, e2) take two Expression objects, while NotExpression$create(e1) takes a single Expression.

Super class

arrow::Object -> Expression

Methods

Public methods

• Expression$ToString()

• Expression$clone()

Inherited methods

• arrow::Object$initialize()

• arrow::Object$pointer()

• arrow::Object$print()

• arrow::Object$set_pointer()

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Method ToString()

Usage

Expression$ToString()

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Method clone()

The objects of this class are cloneable with this method.

Usage

Expression$clone(deep = FALSE)

Arguments

deep

Whether to make a deep clone.

Super classes

arrow::Object -> arrow::Expression -> FieldExpression

Methods

Public methods

• FieldExpression$clone()

Inherited methods

• arrow::Object$initialize()

• arrow::Object$pointer()

• arrow::Object$print()

• arrow::Object$set_pointer()

• arrow::Expression$ToString()

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Method clone()

The objects of this class are cloneable with this method.

Usage

FieldExpression$clone(deep = FALSE)

Arguments

deep

Whether to make a deep clone.

Super classes

arrow::Object -> arrow::Expression -> ScalarExpression

Methods

Public methods

• ScalarExpression$clone()

Inherited methods

• arrow::Object$initialize()

• arrow::Object$pointer()

• arrow::Object$print()

• arrow::Object$set_pointer()

• arrow::Expression$ToString()

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Method clone()

The objects of this class are cloneable with this method.

Usage

ScalarExpression$clone(deep = FALSE)

Arguments

deep

Whether to make a deep clone.

Super classes

arrow::Object -> arrow::Expression -> ComparisonExpression

Methods

Public methods

• ComparisonExpression$clone()

Inherited methods

• arrow::Object$initialize()

• arrow::Object$pointer()

• arrow::Object$print()

• arrow::Object$set_pointer()

• arrow::Expression$ToString()

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Method clone()

The objects of this class are cloneable with this method.

Usage

ComparisonExpression$clone(deep = FALSE)

Arguments

deep

Whether to make a deep clone.

Super classes

arrow::Object -> arrow::Expression -> AndExpression

Methods

Public methods

• AndExpression$clone()

Inherited methods

• arrow::Object$initialize()

• arrow::Object$pointer()

• arrow::Object$print()

• arrow::Object$set_pointer()

• arrow::Expression$ToString()

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Method clone()

The objects of this class are cloneable with this method.

Usage

AndExpression$clone(deep = FALSE)

Arguments

deep

Whether to make a deep clone.

Super classes

arrow::Object -> arrow::Expression -> OrExpression

Methods

Public methods

• OrExpression$clone()

Inherited methods

• arrow::Object$initialize()

• arrow::Object$pointer()

• arrow::Object$print()

• arrow::Object$set_pointer()

• arrow::Expression$ToString()

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Method clone()

The objects of this class are cloneable with this method.

Usage

OrExpression$clone(deep = FALSE)

Arguments

deep

Whether to make a deep clone.

Super classes

arrow::Object -> arrow::Expression -> NotExpression

Methods

Public methods

• NotExpression$clone()

Inherited methods

• arrow::Object$initialize()

• arrow::Object$pointer()

• arrow::Object$print()

• arrow::Object$set_pointer()

• arrow::Expression$ToString()

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Method clone()

The objects of this class are cloneable with this method.

Usage

NotExpression$clone(deep = FALSE)

Arguments

deep

Whether to make a deep clone.