snorkel.map.LambdaMapper

class snorkel.map.LambdaMapper(name, f, pre=None, memoize=False, memoize_key=None)

Bases: snorkel.map.core.BaseMapper

Define a mapper from a function.

Convenience class for mappers that execute a simple function with no set up. The function should map from an input data point to a new data point directly, unlike Mapper.run. The original data point will not be updated, so in-place operations are safe.

Parameters

• name (str) – Name of mapper

• f (Callable[[Any], Optional[Any]]) – Function executing the mapping operation

• pre (Optional[List[BaseMapper]]) – Mappers to run before this mapper is executed

• memoize (bool) – Memoize mapper outputs?

• memoize_key (Optional[Callable[[Any], Hashable]]) – Hashing function to handle the memoization (default to snorkel.map.core.get_hashable)

__init__(name, f, pre=None, memoize=False, memoize_key=None)

Initialize self. See help(type(self)) for accurate signature.

Return type

None

Methods

__init__(name, f[, pre, memoize, memoize_key])	Initialize self.
reset_cache()	Reset the memoization cache.

__call__(x)

Run mapping function on input data point.

Deep copies the data point first so as not to make accidental in-place changes. If memoize is set to True, an internal cache is checked for results. If no cached results are found, the computed results are added to the cache.

Parameters

x (Any) – Data point to run mapping function on

Returns

Mapped data point of same format but possibly different fields

Return type

DataPoint

reset_cache()

Reset the memoization cache.

Return type

None