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.
import logging import pandas as pd from featuretools.utils.gen_utils import make_tqdm_iterator from featuretools.variable_types.variable import Discrete logger = logging.getLogger('featuretools') DEFAULT_TOP_N = 10 [docs]def encode_features(feature_matrix, features, top_n=DEFAULT_TOP_N, include_unknown=True, to_encode=None, inplace=False, drop_first=False, verbose=False): """Encode categorical features Args: feature_matrix (pd.DataFrame): Dataframe of features. features (list[PrimitiveBase]): Feature definitions in feature_matrix. top_n (int or dict[string -> int]): Number of top values to include. If dict[string -> int] is used, key is feature name and value is the number of top values to include for that feature. If a feature's name is not in dictionary, a default value of 10 is used. include_unknown (pd.DataFrame): Add feature encoding an unknown class. defaults to True to_encode (list[str]): List of feature names to encode. features not in this list are unencoded in the output matrix defaults to encode all necessary features. inplace (bool): Encode feature_matrix in place. Defaults to False. drop_first (bool): Whether to get k-1 dummies out of k categorical levels by removing the first level. defaults to False verbose (str): Print progress info. Returns: (pd.Dataframe, list) : encoded feature_matrix, encoded features Example: .. ipython:: python :suppress: from featuretools.tests.testing_utils import make_ecommerce_entityset import featuretools as ft es = make_ecommerce_entityset() .. ipython:: python f1 = ft.Feature(es["log"]["product_id"]) f2 = ft.Feature(es["log"]["purchased"]) f3 = ft.Feature(es["log"]["value"]) features = [f1, f2, f3] ids = [0, 1, 2, 3, 4, 5] feature_matrix = ft.calculate_feature_matrix(features, es, instance_ids=ids) fm_encoded, f_encoded = ft.encode_features(feature_matrix, features) f_encoded fm_encoded, f_encoded = ft.encode_features(feature_matrix, features, top_n=2) f_encoded fm_encoded, f_encoded = ft.encode_features(feature_matrix, features, include_unknown=False) f_encoded fm_encoded, f_encoded = ft.encode_features(feature_matrix, features, to_encode=['purchased']) f_encoded fm_encoded, f_encoded = ft.encode_features(feature_matrix, features, drop_first=True) f_encoded """ if not isinstance(feature_matrix, pd.DataFrame): msg = "feature_matrix must be a Pandas DataFrame" raise TypeError(msg) if inplace: X = feature_matrix else: X = feature_matrix.copy() old_feature_names = set() for feature in features: for fname in feature.get_feature_names(): assert fname in X.columns, ("Feature %s not found in feature matrix" % (fname)) old_feature_names.add(fname) pass_through = [col for col in X.columns if col not in old_feature_names] if verbose: iterator = make_tqdm_iterator(iterable=features, total=len(features), desc="Encoding pass 1", unit="feature") else: iterator = features new_feature_list = [] new_columns = [] encoded_columns = set() for f in iterator: # TODO: features with multiple columns are not encoded by this method, # which can cause an "encoded" matrix with non-numeric vlaues is_discrete = issubclass(f.variable_type, Discrete) if (f.number_output_features > 1 or not is_discrete): if f.number_output_features > 1: logger.warning("Feature %s has multiple columns and will not " "be encoded. This may result in a matrix with" " non-numeric values." % (f)) new_feature_list.append(f) new_columns.extend(f.get_feature_names()) continue if to_encode is not None and f.get_name() not in to_encode: new_feature_list.append(f) new_columns.extend(f.get_feature_names()) continue val_counts = X[f.get_name()].value_counts().to_frame() index_name = val_counts.index.name if index_name is None: if 'index' in val_counts.columns: index_name = 'level_0' else: index_name = 'index' val_counts.reset_index(inplace=True) val_counts = val_counts.sort_values([f.get_name(), index_name], ascending=False) val_counts.set_index(index_name, inplace=True) select_n = top_n if isinstance(top_n, dict): select_n = top_n.get(f.get_name(), DEFAULT_TOP_N) if drop_first: select_n = min(len(val_counts), top_n) select_n = max(select_n - 1, 1) unique = val_counts.head(select_n).index.tolist() for label in unique: add = f == label add_name = add.get_name() new_feature_list.append(add) new_columns.append(add_name) encoded_columns.add(add_name) X[add_name] = (X[f.get_name()] == label) if include_unknown: unknown = f.isin(unique).NOT().rename(f.get_name() + " is unknown") unknown_name = unknown.get_name() new_feature_list.append(unknown) new_columns.append(unknown_name) encoded_columns.add(unknown_name) X[unknown_name] = (~X[f.get_name()].isin(unique)) X.drop(f.get_name(), axis=1, inplace=True) new_columns.extend(pass_through) new_X = X[new_columns] iterator = new_X.columns if verbose: iterator = make_tqdm_iterator(iterable=new_X.columns, total=len(new_X.columns), desc="Encoding pass 2", unit="feature") for c in iterator: if c in encoded_columns: try: new_X[c] = pd.to_numeric(new_X[c], errors='raise') except (TypeError, ValueError): pass return new_X, new_feature_list