Value

Absent

Sentinel class to represent value absence.

ValuePath

Bases: str

A path-like string for accessing nested mappings value.

__new__

__new__(path: str, *, separator: str | None = None) -> Self

Create a new ValuePath object from a path string.

Parameters:

Name	Type	Description	Default
path	str	path string of a value inside a mapping object.	required
separator	str | None	custom separator to use instead of the default.	None

get_from

get_from(mapping: Mapping[Any, V], default: V | None | Absent = ABSENT, *, raise_if_absent: bool = False) -> Any | None | Absent

Get the value describe by the path inside mapping object.

The value returns can be the sentinel ABSENT to differentiate real None value of default.

Parameters:

Name	Type	Description	Default
mapping	Mapping[Any, V]	Dictionary or mapping object to lookup.	required
default	V | None | Absent	Default value if key not found. By default return the sentinel value ABSENT.	ABSENT
raise_if_absent	bool	Flag to raise ValueAbsentError if missing key. Default False	False

Note

Support both string and integer keys.

Raises:

Type	Description
ValueAbsentError	if parameter raise_if_absent set, and key is missing.

get

get(mapping: Mapping[Any, V], default: V | None | Absent = ABSENT, *, raise_if_absent: bool = False) -> Any | None | Absent

Get the value describe by the path inside mapping object.

get is deprecated, use get_from instead.

The value returns can be the sentinel ABSENT to differentiate real None value of default.

Parameters:

Name	Type	Description	Default
mapping	Mapping[Any, V]	Dictionary or mapping object to lookup.	required
default	V | None | Absent	Default value if key not found. By default return the sentinel value ABSENT.	ABSENT
raise_if_absent	bool	Flag to raise ValueAbsentError if missing key. Default False	False

Note

Support both string and integer keys.

Raises:

Type	Description
ValueAbsentError	if parameter raise_if_absent set, and key is missing.

Value

Value(value_path: str, mapper: Mapper[Any, Any] | None = None)

Bases: Condition

Condition based on a value at a certain path in an event.

Parameters:

Name	Type	Description	Default
value_path	str	The path to the value in the event.	required
mapper	Mapper[Any, Any] | None	mapper to transform value before checking predicates on it.	None

root classmethod

root() -> Self

Initialize value targeting condition over the event itself.

Examples:

Value.root().contains("a").check(my_dict)
#  is equivalent to.
"a" in my_dict

check

check(event: Event[V], *, raise_if_absent: bool = False) -> bool

Check the given event respect the value condition.

By default, the event fails the check if the value is absent, an error can be raised, by setting the flag raise_if_absent.

Raises:

Type	Description
NoPredicateError	when no predicate has been set.
ValueAbsentError	if a key define by the path is missing in event.

is_truthy

is_truthy() -> Self

Add value is truthy check to the condition.

is_falsy

is_falsy() -> Self

Add value is truthy check to the condition.

equals

equals(expected: Any) -> Self

Add value equals the expected value check to the condition.

Parameters:

Name	Type	Description	Default
expected	Any	The expected value.	required

match_regex

match_regex(regex: Pattern[str]) -> Self

match_regex(regex: str, flags: RegexFlag | int = 0) -> Self

match_regex(regex: Pattern[str] | str, flags: RegexFlag | int = 0) -> Self

Add value matches the given regex pattern check to the condition.

Parameters:

Name	Type	Description	Default
regex	Pattern[str] | str	regex to match (either a string or a Pattern)	required
flags	RegexFlag | int	regex flags; should bot be passed with a pattern.	0

Raises:

Type	Description
TypeError	when passing flags whereas a Pattern have been passed

one_of

one_of(options: Container[Any]) -> Self

Add value is one of the given options check to the condition.

Parameters:

Name	Type	Description	Default
options	Container[Any]	The container of options.	required

contains

contains(*items: Any) -> Self

Add value contains all the given items to the condition.

Parameters:

Name	Type	Description	Default
items	Any	The items to check for.	()

is_not_empty

is_not_empty() -> Self

Add value is not empty to the condition.

is_length

is_length(length: int) -> Self

Add value has the specified size to the condition.

Parameters:

Name	Type	Description	Default
length	int	The length expected.	required

match

match(predicate: Predicate[Any]) -> Self

Add value matches the given predicate to the condition.

Parameters:

Name	Type	Description	Default
predicate	Predicate[Any]	The predicate to apply.	required

combine

combine(*predicates: Predicate[Any]) -> Predicate[Any]

Combine all provided predicates into a single predicate.

Parameters:

Name	Type	Description	Default
predicates	Predicate[Any]	Predicates to combine.	()