snorkel.map.LambdaMapper

class snorkel.map.LambdaMapper(name, f, pre=None, memoize=False)[source]

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?

__init__(name, f, pre=None, memoize=False)[source]

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

Return type

None

Methods

__init__(name, f[, pre, memoize])

Initialize self.

reset_cache()

Reset the memoization cache.

__call__(x)[source]

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()[source]

Reset the memoization cache.

Return type

None