feature-schema 0.1.3

A lightweight package to extract, document, and validate feature schemas from pandas DataFrames for ML workflows.

feature_schema

feature_schema is a lightweight Python package that automatically extracts and documents feature metadata from a pandas DataFrame.
It’s designed for machine learning workflows where you need to understand, validate, or dynamically generate user inputs for model features.

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Features

• Extract feature name
• Auto-detect feature types (int, float, string, bool, datetime)
• Numeric metadata: min, max, range
• Categorical metadata: unique values & counts
• Nullability check: detect if features contain missing values
• Human-readable docs (__str__) for quick schema inspection
• Exportable schema to dict / DataFrame for further use

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Installation

pip install feature_schema

Usage

1. Create the Schema for a DataFrame

import pandas as pd
from feature_schema import FeatureSchema

# Sample dataset
df = pd.DataFrame({
    "age": [25, 30, 40, 22],
    "salary": [50000.0, 60000.5, 80000.2, 45000.0],
    "city": ["NY", "SF", "LA", "NY"]
})

# Create Feature schema object
fs = FeatureSchema(df)

# Print schema (human readable)
print(fs.to_dict())

Output:

[
    {'column_name': 'age', 'dtype': 'int64', 'type': 'int', 'nullable': np.False_, 'min': 22.0, 'max': 40.0, 'unique_values': 4}, {'column_name': 'salary', 'dtype': 'float64', 'type': 'float', 'nullable': np.False_, 'min': 45000.0, 'max': 80000.2, 'unique_values': 4}, {'column_name': 'city', 'dtype': 'object', 'type': 'string', 'nullable': np.False_, 'unique_values': 3, 'unique_list': ['NY', 'SF', 'LA']}
]

2. Export Schema as Dictionary / DataFrame

# As dictionary
schema_dict = fs.to_dict()
print(schema_dict)

# As DataFrame
schema_df = fs.to_dataframe()
print(schema_df)

Why Use feature_schema?

• No more hardcoding feature names, types, and ranges
• Auto-generate Streamlit forms or FastAPI validation schemas
• Save schema along with ML models for reproducibility
• Helps teams document datasets automatically
• Helps to validate input