one_hot_encoder¶
Operator to encode (transform) categorical features as a one-hot numeric array.
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class
tasrif.processing_pipeline.custom.one_hot_encoder.OneHotEncoderOperator(feature_names: list, drop_first: bool = True, separator: str = ',')¶ Encodes categorical column features from existing features in the data frame. This operator works on a 2D data frames where the columns represent the features. A feature column with X different values will be replaced by X (or X-1) new column features.
Examples
>>> import pandas as pd >>> from tasrif.processing_pipeline.custom import OneHotEncoderOperator >>> >>> df = pd.DataFrame({'id': [1, 2, 3], 'colors': ['red', 'white', 'blue'], >>> 'cities': ['Doha', 'Vienna', 'Belo Horizonte'], >>> 'multiple': ["1,2", "1", "1,3"] >>> df id colors cities multiple 0 1 red Doha 1,2 1 2 white Vienna 1 2 3 blue Belo Horizonte 1,3
>>> OneHotEncoderOperator(feature_names=["colors"], drop_first=False).process(df)[0] id cities multiple colors=red colors=white 0 1 Doha 1,2 1 0 1 2 Vienna 1 0 1 2 3 Belo Horizonte 1,3 0 0
>>> OneHotEncoderOperator(feature_names=["colors"], drop_last_expansion=True).process(df)[0] id cities multiple colors=blue colors=red colors=white 0 1 Doha 1,2 0 1 0 1 2 Vienna 1 0 0 1 2 3 Belo Horizonte 1,3 1 0 0
>>> OneHotEncoderOperator(feature_names=["colors", "multiple"], drop_first=False).process(df)[0] id cities colors=blue colors=red colors=white multiple=1 multiple=2 multiple=3 0 1 Doha 0 1 0 1 1 0 1 2 Vienna 0 0 1 1 0 0 2 3 Belo Horizonte 1 0 0 1 0 1
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__init__(feature_names: list, drop_first: bool = True, separator: str = ',')¶ Creates a new instance of OneHotEncoderOperator
- Parameters
feature_names (list) – The list of categorical features that will be one hot encoded
drop_first (bool) – Transforming a category of X values into exactly X columns most of the times is redundant. If the values are NOT multiple choice, any of the new columns can be removed without resulting in loss of information, at least in a ML perspective. Default: False
separator (str) – That is the separator, if any, used when the values in a column are represented as multiple choice. Default: ‘,’
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