light-mlt 0.1.3

Lightweight preprocessing and reversible Modular Linear Tokenization (MLT) utilities for categorical and continuous data.

🧩 Module: light_mlt.py

Lightweight, reproducible preprocessing pipeline for tabular datasets — integrating categorical encoding via Modular Linear Tokenization (MLT) and continuous feature scaling.
Designed for efficient fit/transform workflows with full reversibility and schema persistence.

📘 Reference
Schmitz, T. (2025). light-mlt: Modular Linear Tokenization for Scalable Categorical Encoding.
DOI: 10.5281/zenodo.17467914

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🔖 Key Features

• Deterministic preprocessing for categorical and continuous data
• Append-only vocabulary management (cats_map.pkl)
• Fully reversible categorical encoding via MLT
• Continuous feature scaling with StandardScaler
• Persistent schema for consistent transformations
• Minimal dependencies: numpy, pandas, scikit-learn

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📦 Artifacts

Each fit() operation generates or updates the following artifacts (default directory: light_mlt_artifacts/):

File	Description
schema.pkl	Schema metadata (columns, types, MLT config)
scaler.pkl	Trained StandardScaler for continuous columns
cats_map.pkl	Append-only {label → id} mapping for categorical features
mlt_params.pkl	MLT parameters (p, n, M, Minv) per column
preprocessed.csv	Optional transformed dataset export

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🧪 Detailed Examples

Below are complete examples demonstrating how to use light_mlt.py for preprocessing, transformation, and reversibility.

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1️⃣ Basic Usage

import pandas as pd
from light_mlt import fit_transform, inverse_transform

# Example dataset
df = pd.DataFrame({
    "city": ["São Paulo", "Curitiba", "São Paulo", "Florianópolis"],z
    "vehicle": ["Truck", "Car", "Car", "Bus"],
    "mileage": [12.4, 25.8, 31.5, 18.7],
})

print("=== Original Data ===")
print(df)

# --- Step 1: Fit + Transform ---
df_t, path, token_cols, report = fit_transform(
    df,
    categorical_cols=["city", "vehicle"],
    continuous_cols=["mileage"],
    dir="light_mlt_artifacts/"
)

print("\n=== Transformed Data ===")
print(df_t.head())

print("\nGenerated token columns:", token_cols)
print("Report:", report)

# --- Step 2: Inverse Transform ---
df_rec = inverse_transform(df_t, dir="light_mlt_artifacts/")
print("\n=== Reconstructed Data ===")
print(df_rec)