visitors
BindVisitor
Bases: BooleanExpressionVisitor[BooleanExpression]
Rewrites a boolean expression by replacing unbound references with references to fields in a struct schema.
Parameters:
Name | Type | Description | Default |
---|---|---|---|
schema |
Schema
|
A schema to use when binding the expression. |
required |
case_sensitive |
bool
|
Whether to consider case when binding a reference to a field in a schema, defaults to True. |
required |
Raises:
Type | Description |
---|---|
TypeError
|
In the case a predicate is already bound. |
Source code in pyiceberg/expressions/visitors.py
BooleanExpressionVisitor
Bases: Generic[T]
, ABC
Source code in pyiceberg/expressions/visitors.py
visit_and(left_result, right_result)
abstractmethod
Visit method for an And boolean expression.
Parameters:
Name | Type | Description | Default |
---|---|---|---|
left_result |
T
|
The result of visiting the left side of the expression. |
required |
right_result |
T
|
The result of visiting the right side of the expression. |
required |
Source code in pyiceberg/expressions/visitors.py
visit_bound_predicate(predicate)
abstractmethod
Visit method for a bound predicate in an expression tree.
Parameters:
Name | Type | Description | Default |
---|---|---|---|
predicate |
BoundPredicate[L]
|
An instance of a BoundPredicate. |
required |
visit_false()
abstractmethod
Visit method for an AlwaysFalse boolean expression.
Note: This visit method has no arguments since AlwaysFalse instances have no context.
visit_not(child_result)
abstractmethod
Visit method for a Not boolean expression.
Parameters:
Name | Type | Description | Default |
---|---|---|---|
child_result |
T
|
The result of visiting the child of the Not boolean expression. |
required |
visit_or(left_result, right_result)
abstractmethod
Visit method for an Or boolean expression.
Parameters:
Name | Type | Description | Default |
---|---|---|---|
left_result |
T
|
The result of visiting the left side of the expression. |
required |
right_result |
T
|
The result of visiting the right side of the expression. |
required |
Source code in pyiceberg/expressions/visitors.py
visit_true()
abstractmethod
Visit method for an AlwaysTrue boolean expression.
Note: This visit method has no arguments since AlwaysTrue instances have no context.
visit_unbound_predicate(predicate)
abstractmethod
Visit method for an unbound predicate in an expression tree.
Parameters:
Name | Type | Description | Default |
---|---|---|---|
predicate |
UnboundPredicate[L
|
An instance of an UnboundPredicate. |
required |
Source code in pyiceberg/expressions/visitors.py
BoundBooleanExpressionVisitor
Bases: BooleanExpressionVisitor[T]
, ABC
Source code in pyiceberg/expressions/visitors.py
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|
visit_and(left_result, right_result)
abstractmethod
visit_bound_predicate(predicate)
Visit a bound predicate.
Parameters:
Name | Type | Description | Default |
---|---|---|---|
predicate |
BoundPredicate[L]
|
A bound predicate. |
required |
visit_equal(term, literal)
abstractmethod
visit_false()
abstractmethod
visit_greater_than(term, literal)
abstractmethod
visit_greater_than_or_equal(term, literal)
abstractmethod
visit_in(term, literals)
abstractmethod
visit_is_nan(term)
abstractmethod
visit_is_null(term)
abstractmethod
visit_less_than(term, literal)
abstractmethod
visit_less_than_or_equal(term, literal)
abstractmethod
visit_not(child_result)
abstractmethod
visit_not_equal(term, literal)
abstractmethod
visit_not_in(term, literals)
abstractmethod
visit_not_nan(term)
abstractmethod
visit_not_null(term)
abstractmethod
visit_not_starts_with(term, literal)
abstractmethod
visit_or(left_result, right_result)
abstractmethod
visit_starts_with(term, literal)
abstractmethod
visit_true()
abstractmethod
visit_unbound_predicate(predicate)
Visit an unbound predicate.
Parameters:
Name | Type | Description | Default |
---|---|---|---|
predicate |
UnboundPredicate[L]
|
An unbound predicate. |
required |
Raises: TypeError: This always raises since an unbound predicate is not expected in a bound boolean expression.
Source code in pyiceberg/expressions/visitors.py
bind(schema, expression, case_sensitive)
Travers over an expression to bind the predicates to the schema.
Parameters:
Name | Type | Description | Default |
---|---|---|---|
schema |
Schema
|
A schema to use when binding the expression. |
required |
expression |
BooleanExpression
|
An expression containing UnboundPredicates that can be bound. |
required |
case_sensitive |
bool
|
Whether to consider case when binding a reference to a field in a schema, defaults to True. |
required |
Raises:
Type | Description |
---|---|
TypeError
|
In the case a predicate is already bound. |
Source code in pyiceberg/expressions/visitors.py
expression_to_plain_format(expressions, cast_int_to_datetime=False)
Format a Disjunctive Normal Form expression.
These are the formats that the expression can be fed into:
- https://arrow.apache.org/docs/python/generated/pyarrow.parquet.read_table.html
- https://docs.dask.org/en/stable/generated/dask.dataframe.read_parquet.html
Contrary to normal DNF that may contain Not expressions, but here they should have
been rewritten. This can be done using rewrite_not(...)
.
Keep in mind that this is only used for page skipping, and still needs to filter on a row level.
Parameters:
Name | Type | Description | Default |
---|---|---|---|
expressions |
Tuple[BooleanExpression, ...]
|
Expression in Disjunctive Normal Form. |
required |
Returns:
Type | Description |
---|---|
List[List[Tuple[str, str, Any]]]
|
Formatter filter compatible with Dask and PyArrow. |
Source code in pyiceberg/expressions/visitors.py
visit(obj, visitor)
Apply a boolean expression visitor to any point within an expression.
The function traverses the expression in post-order fashion.
Parameters:
Name | Type | Description | Default |
---|---|---|---|
obj |
BooleanExpression
|
An instance of a BooleanExpression. |
required |
visitor |
BooleanExpressionVisitor[T]
|
An instance of an implementation of the generic BooleanExpressionVisitor base class. |
required |
Raises:
Type | Description |
---|---|
NotImplementedError
|
If attempting to visit an unsupported expression. |