Preprocessing
hgp_lib.preprocessing.binarizer.StandardBinarizer
Converts a mixed-type DataFrame into a purely boolean DataFrame.
Boolean columns are passed through unchanged. Categorical columns are one-hot encoded into one boolean column per unique value. Numeric columns are discretised into bins and then one-hot encoded, using either quantile-based or decision-tree-based binning depending on whether target labels are supplied.
After fit_transform the binarizer stores the learned bin edges and categorical
mappings so that transform can apply the same encoding to new data.
Parameters:
| Name | Type | Description | Default |
|---|---|---|---|
num_bins
|
int
|
Default number of bins for numeric columns. Must be >= 2. Default: |
5
|
column_strategy
|
dict[str, int] | None
|
Per-column override for the number of bins. Keys are column names, values are
the desired bin count (each >= 2). Default: |
None
|
precision
|
int
|
Number of decimal places used when formatting numeric bin boundary names.
Must be >= 0. Default: |
3
|
Examples:
>>> import pandas as pd
>>> from hgp_lib.preprocessing import StandardBinarizer
>>> df = pd.DataFrame({"flag": [True, False, True], "val": [1.0, 2.0, 3.0]})
>>> binarizer = StandardBinarizer(num_bins=2)
>>> result = binarizer.fit_transform(df)
>>> "flag" in result.columns
True
>>> result["flag"].tolist()
[True, False, True]
>>> result
flag val < 2.000 2.000 <= val
0 True True False
1 False True False
2 True False True
Source code in hgp_lib\preprocessing\binarizer.py
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fit_transform(X, y=None)
Learn the binarisation mapping from X (and optionally y) and return the
transformed boolean DataFrame.
When y is provided, numeric columns are binned using a decision-tree strategy
that maximises class separation. Otherwise, quantile-based binning is used.
Parameters:
| Name | Type | Description | Default |
|---|---|---|---|
X
|
DataFrame
|
Input DataFrame whose columns are boolean, categorical, or numeric. |
required |
y
|
ndarray | None
|
Optional target labels used for supervised (tree-based) binning of numeric
columns. Default: |
None
|
Returns:
| Type | Description |
|---|---|
DataFrame
|
pd.DataFrame: A DataFrame with only boolean columns. |
Raises:
| Type | Description |
|---|---|
TypeError
|
If |
ValueError
|
If a column has an unsupported dtype. |
Examples:
>>> import numpy as np
>>> import pandas as pd
>>> from hgp_lib.preprocessing import StandardBinarizer
>>> df = pd.DataFrame({"x": [1.0, 2.0, 3.0, 4.0]})
>>> binarizer = StandardBinarizer(num_bins=2)
>>> result = binarizer.fit_transform(df)
>>> result.shape
(4, 2)
>>> all(result.dtypes == bool)
True
Source code in hgp_lib\preprocessing\binarizer.py
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transform(X)
Apply the previously learned binarisation to new data.
The binarizer must have been fitted via fit_transform before calling this method.
The input DataFrame must have the same columns (in the same order and with the same
dtypes) as the one used during fitting.
Parameters:
| Name | Type | Description | Default |
|---|---|---|---|
X
|
DataFrame
|
Input DataFrame with the same schema as the fitting data. |
required |
Returns:
| Type | Description |
|---|---|
DataFrame
|
pd.DataFrame: A boolean DataFrame with the same column layout as the fitted output. |
Raises:
| Type | Description |
|---|---|
TypeError
|
If |
ValueError
|
If the binarizer has not been fitted yet, or if a column has an unsupported dtype. |
Examples:
>>> import pandas as pd
>>> from hgp_lib.preprocessing import StandardBinarizer
>>> train = pd.DataFrame({"x": [1.0, 2.0, 3.0, 4.0]})
>>> binarizer = StandardBinarizer(num_bins=2)
>>> _ = binarizer.fit_transform(train)
>>> test = pd.DataFrame({"x": [1.5, 3.5]})
>>> result = binarizer.transform(test)
>>> result.shape
(2, 2)
Source code in hgp_lib\preprocessing\binarizer.py
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hgp_lib.preprocessing.utils.load_data(data_path)
Load features and labels from a CSV or HDF file.
The file must contain a column named "target" which is used as the label
array. All other columns are returned as the feature DataFrame. Labels are
cast to bool.
Parameters:
| Name | Type | Description | Default |
|---|---|---|---|
data_path
|
str
|
Path to a |
required |
Returns:
| Type | Description |
|---|---|
DataFrame
|
Tuple[pd.DataFrame, ndarray]: |
ndarray
|
feature DataFrame (without the target column) and |
Tuple[DataFrame, ndarray]
|
boolean numpy array. |
Raises:
| Type | Description |
|---|---|
FileNotFoundError
|
If |
ValueError
|
If the file extension is not |
RuntimeError
|
If no |
Examples:
>>> import tempfile, os
>>> import pandas as pd
>>> from hgp_lib.preprocessing.utils import load_data
>>> df = pd.DataFrame({"x": [1, 2, 3], "target": [1, 0, 1]})
>>> with tempfile.TemporaryDirectory() as d:
... path = os.path.join(d, "tmp.csv")
... df.to_csv(path, index=False)
... data, labels = load_data(path)
>>> list(data.columns)
['x']
>>> labels.tolist()
[True, False, True]
Source code in hgp_lib\preprocessing\utils.py
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