NOTICE

The upcoming release of Featuretools 1.0.0 contains several breaking changes. Users are encouraged to test this version prior to release by installing from GitHub:

pip install https://github.com/alteryx/featuretools/archive/woodwork-integration.zip

For details on migrating to the new version, refer to Transitioning to Featuretools Version 1.0. Please report any issues in the Featuretools GitHub repo or by messaging in Alteryx Open Source Slack.

Source code for featuretools.primitives.base.transform_primitive_base

import copy
import functools
import inspect

from featuretools.primitives.base.primitive_base import PrimitiveBase
from featuretools.primitives.base.utils import inspect_function_args


class TransformPrimitive(PrimitiveBase):
    """Feature for entity that is a based off one or more other features
        in that entity."""
    # (bool) If True, feature function depends on all values of entity
    #   (and will receive these values as input, regardless of specified instance ids)
    uses_full_entity = False

    def generate_name(self, base_feature_names):
        return u"%s(%s%s)" % (
            self.name.upper(),
            u", ".join(base_feature_names),
            self.get_args_string(),
        )

    def generate_names(self, base_feature_names):
        n = self.number_output_features
        base_name = self.generate_name(base_feature_names)
        return [base_name + "[%s]" % i for i in range(n)]


def make_trans_primitive(function, input_types, return_type, name=None,
                         description=None, cls_attributes=None,
                         uses_calc_time=False, commutative=False,
                         number_output_features=1):
    '''Returns a new transform primitive class

    Args:
        function (function): Function that takes in a series and applies some
            transformation to it.

        input_types (list[Variable]): Variable types of the inputs.

        return_type (Variable): Variable type of return.

        name (str): Name of the primitive. If no name is provided, the name
            of `function` will be used.

        description (str): Description of primitive.

        cls_attributes (dict[str -> anytype]): Custom attributes to be added to
            class. Key is attribute name, value is the attribute value.

        uses_calc_time (bool): If True, the cutoff time the feature is being
            calculated at will be passed to the function as the keyword
            argument 'time'.

        commutative (bool): If True, will only make one feature per unique set
            of base features.

        number_output_features (int): The number of output features (columns in
            the matrix) associated with this feature.

    Example:
        .. ipython :: python

            from featuretools.primitives import make_trans_primitive
            from featuretools.variable_types import Variable, Boolean

            def pd_is_in(array, list_of_outputs=None):
                if list_of_outputs is None:
                    list_of_outputs = []
                return pd.Series(array).isin(list_of_outputs)

            def isin_generate_name(self):
                return u"%s.isin(%s)" % (self.base_features[0].get_name(),
                                         str(self.kwargs['list_of_outputs']))

            IsIn = make_trans_primitive(
                function=pd_is_in,
                input_types=[Variable],
                return_type=Boolean,
                name="is_in",
                description="For each value of the base feature, checks "
                "whether it is in a list that provided.",
                cls_attributes={"generate_name": isin_generate_name})
    '''
    if description is None:
        default_description = 'A custom transform primitive'
        doc = inspect.getdoc(function)
        description = doc if doc is not None else default_description
    # dictionary that holds attributes for class
    cls = {"__doc__": description}
    if cls_attributes is not None:
        cls.update(cls_attributes)

    # creates the new class and set name and types
    name = name or function.__name__
    new_class = type(name, (TransformPrimitive,), cls)
    new_class.name = name
    new_class.input_types = input_types
    new_class.return_type = return_type
    new_class.commutative = commutative
    new_class.number_output_features = number_output_features
    new_class, default_kwargs = inspect_function_args(new_class,
                                                      function,
                                                      uses_calc_time)

    if len(default_kwargs) > 0:
        new_class.default_kwargs = default_kwargs

        def new_class_init(self, *args, **kwargs):
            self.kwargs = copy.deepcopy(self.default_kwargs)
            self.kwargs.update(kwargs)
            self.partial = functools.partial(function, **self.kwargs)
            self.partial.__name__ = name

        new_class.__init__ = new_class_init
        new_class.get_function = lambda self: self.partial
    else:
        # creates a lambda function that returns function every time
        new_class.get_function = lambda self, f=function: f

    return new_class