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""" |
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Functions for data cleaning. |
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:author: Andreas Kanz |
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""" |
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# Imports |
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import itertools |
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import numpy as np |
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import pandas as pd |
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import re |
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from sklearn.base import BaseEstimator, TransformerMixin |
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from typing import List, Optional, Union |
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from klib.describe import corr_mat |
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from klib.utils import ( |
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_diff_report, |
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_drop_duplicates, |
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_missing_vals, |
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_validate_input_bool, |
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_validate_input_range, |
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) |
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__all__ = ["convert_datatypes", "data_cleaning", "drop_missing", "mv_col_handling"] |
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def optimize_ints(data: Union[pd.Series, pd.DataFrame]) -> pd.DataFrame: |
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data = pd.DataFrame(data).copy() |
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ints = data.select_dtypes(include=["int64"]).columns.tolist() |
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data[ints] = data[ints].apply(pd.to_numeric, downcast="integer") |
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return data |
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def optimize_floats(data: Union[pd.Series, pd.DataFrame]) -> pd.DataFrame: |
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data = pd.DataFrame(data).copy() |
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floats = data.select_dtypes(include=["float64"]).columns.tolist() |
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data[floats] = data[floats].apply(pd.to_numeric, downcast="float") |
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return data |
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def clean_column_names(data: pd.DataFrame, hints: bool = True) -> pd.DataFrame: |
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"""Cleans the column names of the provided Pandas Dataframe and optionally provides hints on duplicate and long \ |
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column names. |
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Parameters |
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---------- |
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data : pd.DataFrame |
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Original Dataframe with columns to be cleaned |
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hints : bool, optional |
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Print out hints on column name duplication and colum name length, by default True |
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Returns |
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------- |
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pd.DataFrame |
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andas DataFrame with cleaned column names |
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""" |
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for i, col in enumerate(data.columns): |
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matches = re.findall(re.compile("[a-z][A-Z]"), col) |
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for match in matches: |
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column = col.replace(match, match[0] + "_" + match[1]) |
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data.rename(columns={data.columns[i]: column}, inplace=True) |
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for i, col in enumerate(data.columns): |
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matches = re.findall(re.compile("[a-z][A-Z]"), col) |
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column = col |
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for match in matches: |
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column = column.replace(match, match[0] + "_" + match[1]) |
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data.rename(columns={data.columns[i]: column}, inplace=True) |
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data.columns = ( |
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data.columns.str.replace("(", " ") |
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.str.replace(")", " ") |
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.str.replace("'", " ") |
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.str.replace('"', " ") |
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.str.replace("/", " ") |
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.str.replace("-", "") |
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.str.replace("+", " plus ") |
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.str.replace("-", " minus ") |
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.str.replace("*", " times ") |
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.str.replace("ä", "ae") |
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.str.replace("ö", "oe") |
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.str.replace("ü", "ue") |
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.str.replace("ß", "ss") |
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.str.replace("%", " percent ") |
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.str.replace("$", " dollar ") |
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.str.replace("€", " euro ") |
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.str.replace("@", " at ") |
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.str.replace("#", " number ") |
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.str.replace("&", " and ") |
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.str.lower() |
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.str.strip() |
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.str.replace(" ", " ") |
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.str.replace(" ", " ") |
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.str.replace(" ", "_") |
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) |
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dupl_idx = [i for i, x in enumerate(data.columns.duplicated()) if x] |
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if len(dupl_idx) > 0: |
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dupl_before = data.columns[dupl_idx].tolist() |
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data.columns = [ |
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col if col not in data.columns[:i] else col + "_" + str(i) for i, col in enumerate(data.columns) |
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] |
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if hints: |
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print( |
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f"- Duplicate column names detected! Columns with index {dupl_idx} and names {dupl_before}) have \n\ |
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been renamed to {data.columns[dupl_idx].tolist()}." |
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) |
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long_col_names = [x for x in data.columns if len(x) > 25] |
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if len(long_col_names) > 0 and hints: |
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print( |
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f"- Long column names detected (>25 characters)! Consider renaming the following columns {long_col_names}." |
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) |
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return data |
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def convert_datatypes( |
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data: pd.DataFrame, |
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category: bool = True, |
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cat_threshold: float = 0.05, |
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cat_exclude: Optional[List[Union[str, int]]] = None, |
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) -> pd.DataFrame: |
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""" Converts columns to best possible dtypes using dtypes supporting pd.NA. Temporarily not converting to integers \ |
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due to an issue in pandas. This is expected to be fixed in pandas 1.1. \ |
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See https://github.com/pandas-dev/pandas/issues/33803 |
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Parameters |
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---------- |
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data : pd.DataFrame |
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2D dataset that can be coerced into Pandas DataFrame |
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category : bool, optional |
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Change dtypes of columns with dtype "object" to "category". Set threshold using cat_threshold or exclude \ |
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columns using cat_exclude, by default True |
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cat_threshold : float, optional |
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Ratio of unique values below which categories are inferred and column dtype is changed to categorical, \ |
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by default 0.05 |
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cat_exclude : Optional[List[Union[str, int]]], optional |
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List of columns to exclude from categorical conversion, by default None |
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Returns |
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------- |
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pd.DataFrame |
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Pandas DataFrame with converted Datatypes |
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""" |
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# Validate Inputs |
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_validate_input_bool(category, "Category") |
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_validate_input_range(cat_threshold, "cat_threshold", 0, 1) |
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cat_exclude = [] if cat_exclude is None else cat_exclude.copy() |
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data = pd.DataFrame(data).copy() |
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for col in data.columns: |
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unique_vals_ratio = data[col].nunique(dropna=False) / data.shape[0] |
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if ( |
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category |
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and unique_vals_ratio < cat_threshold |
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and col not in cat_exclude |
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and data[col].dtype == "object" |
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): |
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data[col] = data[col].astype("category") |
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# convert_ints = True if int(pd.__version__.replace(".", "")) >= 110 else False |
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data[col] = data[col].convert_dtypes( |
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infer_objects=True, convert_string=True, convert_integer=False, convert_boolean=True |
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) |
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data = optimize_ints(data) |
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data = optimize_floats(data) |
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return data |
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def drop_missing( |
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data: pd.DataFrame, |
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drop_threshold_cols: float = 1, |
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drop_threshold_rows: float = 1, |
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col_exclude: Optional[List[str]] = None, |
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) -> pd.DataFrame: |
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""" Drops completely empty columns and rows by default and optionally provides flexibility to loosen restrictions \ |
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to drop additional non-empty columns and rows based on the fraction of NA-values. |
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Parameters |
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---------- |
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data : pd.DataFrame |
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2D dataset that can be coerced into Pandas DataFrame |
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drop_threshold_cols : float, optional |
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Drop columns with NA-ratio equal to or above the specified threshold, by default 1 |
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drop_threshold_rows : float, optional |
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Drop rows with NA-ratio equal to or above the specified threshold, by default 1 |
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col_exclude : Optional[List[str]], optional |
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Specify a list of columns to exclude from dropping. The excluded columns do not affect the drop thresholds, by \ |
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default None |
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Returns |
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------- |
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pd.DataFrame |
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Pandas DataFrame without any empty columns or rows |
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Notes |
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----- |
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Columns are dropped first |
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""" |
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# Validate Inputs |
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_validate_input_range(drop_threshold_cols, "drop_threshold_cols", 0, 1) |
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_validate_input_range(drop_threshold_rows, "drop_threshold_rows", 0, 1) |
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col_exclude = [] if col_exclude is None else col_exclude.copy() |
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data_exclude = data[col_exclude] |
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data = pd.DataFrame(data).copy() |
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data_dropped = data.drop(columns=col_exclude) |
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data_dropped = data_dropped.drop( |
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columns=data_dropped.loc[:, _missing_vals(data)["mv_cols_ratio"] > drop_threshold_cols].columns |
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).dropna(axis=1, how="all") |
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data = pd.concat([data_dropped, data_exclude], axis=1) |
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data_cleaned = data.drop( |
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index=data.loc[_missing_vals(data)["mv_rows_ratio"] > drop_threshold_rows, :].index |
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).dropna(axis=0, how="all") |
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return data_cleaned |
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def data_cleaning( |
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data: pd.DataFrame, |
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drop_threshold_cols: float = 0.9, |
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drop_threshold_rows: float = 0.9, |
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drop_duplicates: bool = True, |
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convert_dtypes: bool = True, |
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col_exclude: Optional[List[str]] = None, |
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category: bool = True, |
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cat_threshold: float = 0.03, |
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cat_exclude: Optional[List[Union[str, int]]] = None, |
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clean_col_names: bool = True, |
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show: str = "changes", |
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) -> pd.DataFrame: |
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""" Perform initial data cleaning tasks on a dataset, such as dropping single valued and empty rows, \ |
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empty columns as well as optimizing the datatypes. |
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Parameters |
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---------- |
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data : pd.DataFrame |
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2D dataset that can be coerced into Pandas DataFrame |
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drop_threshold_cols : float, optional |
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Drop columns with NA-ratio equal to or above the specified threshold, by default 0.9 |
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drop_threshold_rows : float, optional |
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Drop rows with NA-ratio equal to or above the specified threshold, by default 0.9 |
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drop_duplicates : bool, optional |
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Drop duplicate rows, keeping the first occurence. This step comes after the dropping of missing values, by \ |
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default True |
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convert_dtypes : bool, optional |
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Convert dtypes using pd.convert_dtypes(), by default True |
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col_exclude : Optional[List[str]], optional |
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Specify a list of columns to exclude from dropping, by default None |
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category : bool, optional |
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Enable changing dtypes of 'object' columns to "category". Set threshold using cat_threshold. Requires \ |
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convert_dtypes=True, by default True |
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cat_threshold : float, optional |
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Ratio of unique values below which categories are inferred and column dtype is changed to categorical, by \ |
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default 0.03 |
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267
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cat_exclude : Optional[List[str]], optional |
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268
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List of columns to exclude from categorical conversion, by default None |
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clean_column_names: bool, optional |
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Cleans the column names and provides hints on duplicate and long names, by default True |
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show : str, optional |
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{'all', 'changes', None}, by default "changes" |
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Specify verbosity of the output: |
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* 'all': Print information about the data before and after cleaning as well as information about changes \ |
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and memory usage (deep). Please be aware, that this can slow down the function by quite a bit. |
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* 'changes': Print out differences in the data before and after cleaning. |
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* None: No information about the data and the data cleaning is printed. |
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Returns |
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281
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------- |
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282
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pd.DataFrame |
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Cleaned Pandas DataFrame |
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285
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See also |
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286
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-------- |
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287
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convert_datatypes: Convert columns to best possible dtypes. |
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288
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drop_missing : Flexibly drop columns and rows.a |
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289
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_memory_usage: Gives the total memory usage in megabytes. |
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290
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_missing_vals: Metrics about missing values in the dataset. |
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291
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292
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Notes |
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293
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----- |
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294
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The category dtype is not grouped in the summary, unless it contains exactly the same categories. |
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295
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""" |
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296
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297
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# Validate Inputs |
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298
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_validate_input_range(drop_threshold_cols, "drop_threshold_cols", 0, 1) |
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299
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_validate_input_range(drop_threshold_rows, "drop_threshold_rows", 0, 1) |
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300
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_validate_input_bool(drop_duplicates, "drop_duplicates") |
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301
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_validate_input_bool(convert_dtypes, "convert_datatypes") |
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302
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_validate_input_bool(category, "category") |
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_validate_input_range(cat_threshold, "cat_threshold", 0, 1) |
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304
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305
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data = pd.DataFrame(data).copy() |
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data_cleaned = drop_missing(data, drop_threshold_cols, drop_threshold_rows, col_exclude=col_exclude) |
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single_val_cols = data_cleaned.columns[data_cleaned.nunique(dropna=False) == 1].tolist() |
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data_cleaned = data_cleaned.drop(columns=single_val_cols) |
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dupl_rows = None |
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if drop_duplicates: |
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data_cleaned, dupl_rows = _drop_duplicates(data_cleaned) |
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if convert_dtypes: |
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data_cleaned = convert_datatypes( |
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data_cleaned, category=category, cat_threshold=cat_threshold, cat_exclude=cat_exclude |
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) |
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if clean_col_names: |
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data_cleaned = clean_column_names(data_cleaned) |
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_diff_report(data, data_cleaned, dupl_rows=dupl_rows, single_val_cols=single_val_cols, show=show) |
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return data_cleaned |
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class DataCleaner(BaseEstimator, TransformerMixin): |
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""" Wrapper for data_cleaning(). Allows data_cleaning() to be put into a pipeline with similar \ |
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functions (e.g. using MVColHandler() or SubsetPooler()). |
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Parameters: |
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---------´ |
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drop_threshold_cols: float, default 0.9 |
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Drop columns with NA-ratio equal to or above the specified threshold. |
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336
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drop_threshold_rows: float, default 0.9 |
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Drop rows with NA-ratio equal to or above the specified threshold. |
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drop_duplicates: bool, default True |
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Drop duplicate rows, keeping the first occurence. This step comes after the dropping of missing values. |
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342
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convert_dtypes: bool, default True |
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Convert dtypes using pd.convert_dtypes(). |
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345
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col_exclude: list, default None |
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Specify a list of columns to exclude from dropping. |
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348
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category: bool, default True |
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Change dtypes of columns to "category". Set threshold using cat_threshold. Requires convert_dtypes=True |
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351
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cat_threshold: float, default 0.03 |
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Ratio of unique values below which categories are inferred and column dtype is changed to categorical. |
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354
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cat_exclude: list, default None |
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List of columns to exclude from categorical conversion. |
|
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|
357
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show: str, optional |
|
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{'all', 'changes', None}, by default "changes" |
|
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|
Specify verbosity of the output: |
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* 'all': Print information about the data before and after cleaning as well as information about changes \ |
|
361
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|
|
and memory usage (deep). Please be aware, that this can slow down the function by quite a bit. |
|
362
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* 'changes': Print out differences in the data before and after cleaning. |
|
363
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|
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* None: No information about the data and the data cleaning is printed. |
|
364
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|
|
|
|
365
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|
|
Returns |
|
366
|
|
|
------- |
|
367
|
|
|
data_cleaned: Pandas DataFrame |
|
368
|
|
|
""" |
|
369
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|
|
370
|
|
|
def __init__( |
|
371
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self, |
|
372
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|
|
drop_threshold_cols: float = 0.9, |
|
373
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|
|
drop_threshold_rows: float = 0.9, |
|
374
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|
|
drop_duplicates: bool = True, |
|
375
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|
|
convert_dtypes: bool = True, |
|
376
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|
|
col_exclude: Optional[List[str]] = None, |
|
377
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|
|
category: bool = True, |
|
378
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|
|
cat_threshold: float = 0.03, |
|
379
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|
|
cat_exclude: Optional[List[Union[str, int]]] = None, |
|
380
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|
|
show: str = "changes", |
|
381
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|
|
): |
|
382
|
|
|
self.drop_threshold_cols = drop_threshold_cols |
|
383
|
|
|
self.drop_threshold_rows = drop_threshold_rows |
|
384
|
|
|
self.drop_duplicates = drop_duplicates |
|
385
|
|
|
self.convert_dtypes = convert_dtypes |
|
386
|
|
|
self.col_exclude = col_exclude |
|
387
|
|
|
self.category = category |
|
388
|
|
|
self.cat_threshold = cat_threshold |
|
389
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|
|
self.cat_exclude = cat_exclude |
|
390
|
|
|
self.show = show |
|
391
|
|
|
|
|
392
|
|
|
def fit(self, data, target=None): |
|
393
|
|
|
return self |
|
394
|
|
|
|
|
395
|
|
|
def transform(self, data, target=None): |
|
396
|
|
|
data_cleaned = data_cleaning( |
|
397
|
|
|
data, |
|
398
|
|
|
drop_threshold_cols=self.drop_threshold_cols, |
|
399
|
|
|
drop_threshold_rows=self.drop_threshold_rows, |
|
400
|
|
|
drop_duplicates=self.drop_duplicates, |
|
401
|
|
|
convert_dtypes=self.convert_dtypes, |
|
402
|
|
|
col_exclude=self.col_exclude, |
|
403
|
|
|
category=self.category, |
|
404
|
|
|
cat_threshold=self.cat_threshold, |
|
405
|
|
|
cat_exclude=self.cat_exclude, |
|
406
|
|
|
show=self.show, |
|
407
|
|
|
) |
|
408
|
|
|
return data_cleaned |
|
409
|
|
|
|
|
410
|
|
|
|
|
411
|
|
|
def mv_col_handling( |
|
412
|
|
|
data: pd.DataFrame, |
|
413
|
|
|
target: Optional[Union[str, pd.Series, List]] = None, |
|
414
|
|
|
mv_threshold: float = 0.1, |
|
415
|
|
|
corr_thresh_features: float = 0.5, |
|
416
|
|
|
corr_thresh_target: float = 0.3, |
|
417
|
|
|
return_details: bool = False, |
|
418
|
|
|
) -> pd.DataFrame: |
|
419
|
|
|
""" Converts columns with a high ratio of missing values into binary features and eventually drops them based on \ |
|
420
|
|
|
their correlation with other features and the target variable. This function follows a three step process: |
|
421
|
|
|
- 1) Identify features with a high ratio of missing values (above 'mv_threshold'). |
|
422
|
|
|
- 2) Identify high correlations of these features among themselves and with other features in the dataset (above \ |
|
423
|
|
|
'corr_thresh_features'). |
|
424
|
|
|
- 3) Features with high ratio of missing values and high correlation among each other are dropped unless \ |
|
425
|
|
|
they correlate reasonably well with the target variable (above 'corr_thresh_target'). |
|
426
|
|
|
|
|
427
|
|
|
Note: If no target is provided, the process exits after step two and drops columns identified up to this point. |
|
428
|
|
|
|
|
429
|
|
|
Parameters |
|
430
|
|
|
---------- |
|
431
|
|
|
data : pd.DataFrame |
|
432
|
|
|
2D dataset that can be coerced into Pandas DataFrame |
|
433
|
|
|
target : Optional[Union[str, pd.Series, List]], optional |
|
434
|
|
|
Specify target for correlation. I.e. label column to generate only the correlations between each feature \ |
|
435
|
|
|
and the label, by default None |
|
436
|
|
|
mv_threshold : float, optional |
|
437
|
|
|
Value between 0 <= threshold <= 1. Features with a missing-value-ratio larger than mv_threshold are candidates \ |
|
438
|
|
|
for dropping and undergo further analysis, by default 0.1 |
|
439
|
|
|
corr_thresh_features : float, optional |
|
440
|
|
|
Value between 0 <= threshold <= 1. Maximum correlation a previously identified features (with a high mv-ratio) \ |
|
441
|
|
|
is allowed to have with another feature. If this threshold is overstepped, the feature undergoes further \ |
|
442
|
|
|
analysis, by default 0.5 |
|
443
|
|
|
corr_thresh_target : float, optional |
|
444
|
|
|
Value between 0 <= threshold <= 1. Minimum required correlation of a remaining feature (i.e. feature with a \ |
|
445
|
|
|
high mv-ratio and high correlation to another existing feature) with the target. If this threshold is not met \ |
|
446
|
|
|
the feature is ultimately dropped, by default 0.3 |
|
447
|
|
|
return_details : bool, optional |
|
448
|
|
|
Provdies flexibility to return intermediary results, by default False |
|
449
|
|
|
|
|
450
|
|
|
Returns |
|
451
|
|
|
------- |
|
452
|
|
|
pd.DataFrame |
|
453
|
|
|
Updated Pandas DataFrame |
|
454
|
|
|
|
|
455
|
|
|
optional: |
|
456
|
|
|
cols_mv: Columns with missing values included in the analysis |
|
457
|
|
|
drop_cols: List of dropped columns |
|
458
|
|
|
""" |
|
459
|
|
|
|
|
460
|
|
|
# Validate Inputs |
|
461
|
|
|
_validate_input_range(mv_threshold, "mv_threshold", 0, 1) |
|
462
|
|
|
_validate_input_range(corr_thresh_features, "corr_thresh_features", 0, 1) |
|
463
|
|
|
_validate_input_range(corr_thresh_target, "corr_thresh_target", 0, 1) |
|
464
|
|
|
|
|
465
|
|
|
data = pd.DataFrame(data).copy() |
|
466
|
|
|
data_local = data.copy() |
|
467
|
|
|
mv_ratios = _missing_vals(data_local)["mv_cols_ratio"] |
|
468
|
|
|
cols_mv = mv_ratios[mv_ratios > mv_threshold].index.tolist() |
|
469
|
|
|
data_local[cols_mv] = data_local[cols_mv].applymap(lambda x: 1 if not pd.isnull(x) else x).fillna(0) |
|
470
|
|
|
|
|
471
|
|
|
high_corr_features = [] |
|
472
|
|
|
data_temp = data_local.copy() |
|
473
|
|
|
for col in cols_mv: |
|
474
|
|
|
corrmat = corr_mat(data_temp, colored=False) |
|
475
|
|
|
if abs(corrmat[col]).nlargest(2)[1] > corr_thresh_features: |
|
476
|
|
|
high_corr_features.append(col) |
|
477
|
|
|
data_temp = data_temp.drop(columns=[col]) |
|
478
|
|
|
|
|
479
|
|
|
drop_cols = [] |
|
480
|
|
|
if target is None: |
|
481
|
|
|
data = data.drop(columns=high_corr_features) |
|
482
|
|
|
else: |
|
483
|
|
|
corrs = corr_mat(data_local, target=target, colored=False).loc[high_corr_features] |
|
484
|
|
|
drop_cols = corrs.loc[abs(corrs.iloc[:, 0]) < corr_thresh_target].index.tolist() |
|
485
|
|
|
data = data.drop(columns=drop_cols) |
|
486
|
|
|
|
|
487
|
|
|
if return_details: |
|
488
|
|
|
return data, cols_mv, drop_cols |
|
489
|
|
|
|
|
490
|
|
|
return data |
|
491
|
|
|
|
|
492
|
|
|
|
|
493
|
|
|
class MVColHandler(BaseEstimator, TransformerMixin): |
|
494
|
|
|
""" Wrapper for mv_col_handling(). Allows mv_col_handling() to be put into a pipeline with similar \ |
|
495
|
|
|
functions (e.g. using DataCleaner() or SubsetPooler()). |
|
496
|
|
|
|
|
497
|
|
|
Parameters |
|
498
|
|
|
---------- |
|
499
|
|
|
target: string, list, np.array or pd.Series, default None |
|
500
|
|
|
Specify target for correlation. E.g. label column to generate only the correlations between each feature \ |
|
501
|
|
|
and the label. |
|
502
|
|
|
|
|
503
|
|
|
mv_threshold: float, default 0.1 |
|
504
|
|
|
Value between 0 <= threshold <= 1. Features with a missing-value-ratio larger than mv_threshold are candidates \ |
|
505
|
|
|
for dropping and undergo further analysis. |
|
506
|
|
|
|
|
507
|
|
|
corr_thresh_features: float, default 0.6 |
|
508
|
|
|
Value between 0 <= threshold <= 1. Maximum correlation a previously identified features with a high mv-ratio \ |
|
509
|
|
|
is allowed to have with another feature. If this threshold is overstepped, the feature undergoes further \ |
|
510
|
|
|
analysis. |
|
511
|
|
|
|
|
512
|
|
|
corr_thresh_target: float, default 0.3 |
|
513
|
|
|
Value between 0 <= threshold <= 1. Minimum required correlation of a remaining feature (i.e. feature with a \ |
|
514
|
|
|
high mv-ratio and high correlation to another existing feature) with the target. If this threshold is not met \ |
|
515
|
|
|
the feature is ultimately dropped. |
|
516
|
|
|
|
|
517
|
|
|
return_details: bool, default True |
|
518
|
|
|
Provdies flexibility to return intermediary results. |
|
519
|
|
|
|
|
520
|
|
|
Returns |
|
521
|
|
|
------- |
|
522
|
|
|
data: Updated Pandas DataFrame |
|
523
|
|
|
""" |
|
524
|
|
|
|
|
525
|
|
|
def __init__( |
|
526
|
|
|
self, |
|
527
|
|
|
target: Optional[Union[str, pd.Series, List]] = None, |
|
528
|
|
|
mv_threshold: float = 0.1, |
|
529
|
|
|
corr_thresh_features: float = 0.6, |
|
530
|
|
|
corr_thresh_target: float = 0.3, |
|
531
|
|
|
return_details: bool = True, |
|
532
|
|
|
): |
|
533
|
|
|
self.target = target |
|
534
|
|
|
self.mv_threshold = mv_threshold |
|
535
|
|
|
self.corr_thresh_features = corr_thresh_features |
|
536
|
|
|
self.corr_thresh_target = corr_thresh_target |
|
537
|
|
|
self.return_details = return_details |
|
538
|
|
|
|
|
539
|
|
|
def fit(self, data, target=None): |
|
540
|
|
|
return self |
|
541
|
|
|
|
|
542
|
|
|
def transform(self, data, target=None): |
|
543
|
|
|
data, cols_mv, dropped_cols = mv_col_handling( |
|
544
|
|
|
data, |
|
545
|
|
|
target=self.target, |
|
546
|
|
|
mv_threshold=self.mv_threshold, |
|
547
|
|
|
corr_thresh_features=self.corr_thresh_features, |
|
548
|
|
|
corr_thresh_target=self.corr_thresh_target, |
|
549
|
|
|
return_details=self.return_details, |
|
550
|
|
|
) |
|
551
|
|
|
|
|
552
|
|
|
print(f"\nFeatures with MV-ratio > {self.mv_threshold}: {len(cols_mv)}") |
|
553
|
|
|
print("Features dropped:", len(dropped_cols), dropped_cols) |
|
554
|
|
|
|
|
555
|
|
|
return data |
|
556
|
|
|
|
|
557
|
|
|
|
|
558
|
|
|
def pool_duplicate_subsets( |
|
559
|
|
|
data: pd.DataFrame, |
|
560
|
|
|
col_dupl_thresh: float = 0.2, |
|
561
|
|
|
subset_thresh: float = 0.2, |
|
562
|
|
|
min_col_pool: int = 3, |
|
563
|
|
|
exclude: Optional[List[str]] = None, |
|
564
|
|
|
return_details=False, |
|
565
|
|
|
) -> pd.DataFrame: |
|
566
|
|
|
""" Checks for duplicates in subsets of columns and pools them. This can reduce the number of columns in the data \ |
|
567
|
|
|
without loosing much information. Suitable columns are combined to subsets and tested for duplicates. In case \ |
|
568
|
|
|
sufficient duplicates can be found, the respective columns are aggregated into a 'pooled_var' column. \ |
|
569
|
|
|
Identical numbers in the 'pooled_var' column indicate identical information in the respective rows. |
|
570
|
|
|
|
|
571
|
|
|
Note: It is advised to exclude features that provide sufficient informational content by themselves as well \ |
|
572
|
|
|
as the target column by using the "exclude" setting. |
|
573
|
|
|
|
|
574
|
|
|
Parameters |
|
575
|
|
|
---------- |
|
576
|
|
|
data : pd.DataFrame |
|
577
|
|
|
2D dataset that can be coerced into Pandas DataFrame |
|
578
|
|
|
col_dupl_thresh : float, optional |
|
579
|
|
|
Columns with a ratio of duplicates higher than 'col_dupl_thresh' are considered in the further analysis. \ |
|
580
|
|
|
Columns with a lower ratio are not considered for pooling, by default 0.2 |
|
581
|
|
|
subset_thresh : float, optional |
|
582
|
|
|
The first subset with a duplicate threshold higher than 'subset_thresh' is chosen and aggregated. If no subset \ |
|
583
|
|
|
reaches the threshold, the algorithm continues with continuously smaller subsets until 'min_col_pool' is \ |
|
584
|
|
|
reached, by default 0.2 |
|
585
|
|
|
min_col_pool : int, optional |
|
586
|
|
|
Minimum number of columns to pool. The algorithm attempts to combine as many columns as possible to suitable \ |
|
587
|
|
|
subsets and stops when 'min_col_pool' is reached, by default 3 |
|
588
|
|
|
exclude : Optional[List[str]], optional |
|
589
|
|
|
List of column names to be excluded from the analysis. These columns are passed through without modification, \ |
|
590
|
|
|
by default None |
|
591
|
|
|
return_details : bool, optional |
|
592
|
|
|
Provdies flexibility to return intermediary results, by default False |
|
593
|
|
|
|
|
594
|
|
|
Returns |
|
595
|
|
|
------- |
|
596
|
|
|
pd.DataFrame |
|
597
|
|
|
DataFrame with low cardinality columns pooled |
|
598
|
|
|
|
|
599
|
|
|
optional: |
|
600
|
|
|
subset_cols: List of columns used as subset |
|
601
|
|
|
""" |
|
602
|
|
|
|
|
603
|
|
|
# Input validation |
|
604
|
|
|
_validate_input_range(col_dupl_thresh, "col_dupl_thresh", 0, 1) |
|
605
|
|
|
_validate_input_range(subset_thresh, "subset_thresh", 0, 1) |
|
606
|
|
|
_validate_input_range(min_col_pool, "min_col_pool", 0, data.shape[1]) |
|
607
|
|
|
|
|
608
|
|
|
excluded_cols = [] |
|
609
|
|
|
if exclude is not None: |
|
610
|
|
|
excluded_cols = data[exclude] |
|
611
|
|
|
data = data.drop(columns=exclude) |
|
612
|
|
|
|
|
613
|
|
|
subset_cols = [] |
|
614
|
|
|
for i in range(data.shape[1] + 1 - min_col_pool): |
|
615
|
|
|
check_list = [col for col in data.columns if data.duplicated(subset=col).mean() > col_dupl_thresh] |
|
616
|
|
|
|
|
617
|
|
|
if len(check_list) > 0: |
|
618
|
|
|
combinations = itertools.combinations(check_list, len(check_list) - i) |
|
619
|
|
|
else: |
|
620
|
|
|
continue |
|
621
|
|
|
|
|
622
|
|
|
ratios = [*map(lambda comb: data.duplicated(subset=list(comb)).mean(), combinations)] |
|
623
|
|
|
|
|
624
|
|
|
max_ratio = max(ratios) |
|
625
|
|
|
max_idx = np.argmax(ratios) |
|
626
|
|
|
|
|
627
|
|
|
if max_ratio > subset_thresh: |
|
628
|
|
|
best_subset = itertools.islice( |
|
629
|
|
|
itertools.combinations(check_list, len(check_list) - i), max_idx, max_idx + 1 |
|
630
|
|
|
) |
|
631
|
|
|
best_subset = data[list(list(best_subset)[0])] |
|
632
|
|
|
subset_cols = best_subset.columns.tolist() |
|
633
|
|
|
|
|
634
|
|
|
unique_subset = ( |
|
635
|
|
|
best_subset.drop_duplicates().reset_index().rename(columns={"index": "pooled_vars"}) |
|
636
|
|
|
) |
|
637
|
|
|
data = data.merge(unique_subset, how="left", on=best_subset.columns.tolist()).drop( |
|
638
|
|
|
columns=best_subset.columns.tolist() |
|
639
|
|
|
) |
|
640
|
|
|
data.index = pd.RangeIndex(len(data)) |
|
641
|
|
|
break |
|
642
|
|
|
|
|
643
|
|
|
data = pd.concat([data, pd.DataFrame(excluded_cols)], axis=1) |
|
644
|
|
|
|
|
645
|
|
|
if return_details: |
|
646
|
|
|
return data, subset_cols |
|
647
|
|
|
|
|
648
|
|
|
return data |
|
649
|
|
|
|
|
650
|
|
|
|
|
651
|
|
|
class SubsetPooler(BaseEstimator, TransformerMixin): |
|
652
|
|
|
""" Wrapper for pool_duplicate_subsets(). Allows pool_duplicate_subsets() to be put into a pipeline with similar \ |
|
653
|
|
|
functions (e.g. using DataCleaner() or MVColHandler()). |
|
654
|
|
|
|
|
655
|
|
|
Parameters |
|
656
|
|
|
---------- |
|
657
|
|
|
col_dupl_ratio: float, default 0.2 |
|
658
|
|
|
Columns with a ratio of duplicates higher than 'col_dupl_ratio' are considered in the further analysis. \ |
|
659
|
|
|
Columns with a lower ratio are not considered for pooling. |
|
660
|
|
|
|
|
661
|
|
|
dupl_thresh: float, default 0.2 |
|
662
|
|
|
The first subset with a duplicate threshold higher than 'dupl_thresh' is chosen and aggregated. If no subset \ |
|
663
|
|
|
reaches the threshold, the algorithm continues with continuously smaller subsets until 'min_col_pool' is \ |
|
664
|
|
|
reached. |
|
665
|
|
|
|
|
666
|
|
|
min_col_pool: integer, default 3 |
|
667
|
|
|
Minimum number of columns to pool. The algorithm attempts to combine as many columns as possible to suitable \ |
|
668
|
|
|
subsets and stops when 'min_col_pool' is reached. |
|
669
|
|
|
|
|
670
|
|
|
return_details: bool, default False |
|
671
|
|
|
Provdies flexibility to return intermediary results. |
|
672
|
|
|
|
|
673
|
|
|
Returns: |
|
674
|
|
|
------- |
|
675
|
|
|
data: pd.DataFrame |
|
676
|
|
|
""" |
|
677
|
|
|
|
|
678
|
|
|
def __init__(self, col_dupl_thresh=0.2, subset_thresh=0.2, min_col_pool=3, return_details=True): |
|
679
|
|
|
self.col_dupl_thresh = col_dupl_thresh |
|
680
|
|
|
self.subset_thresh = subset_thresh |
|
681
|
|
|
self.min_col_pool = min_col_pool |
|
682
|
|
|
self.return_details = return_details |
|
683
|
|
|
|
|
684
|
|
|
def fit(self, data, target=None): |
|
685
|
|
|
return self |
|
686
|
|
|
|
|
687
|
|
|
def transform(self, data, target=None): |
|
688
|
|
|
data, subset_cols = pool_duplicate_subsets( |
|
689
|
|
|
data, col_dupl_thresh=0.2, subset_thresh=0.2, min_col_pool=3, return_details=True |
|
690
|
|
|
) |
|
691
|
|
|
|
|
692
|
|
|
print("Combined columns:", len(subset_cols), subset_cols) |
|
693
|
|
|
|
|
694
|
|
|
return data |
|
695
|
|
|
|
akanz1 /
klib
