lochan-eda 0.0.2

An automated Exploratory Data Analysis (EDA) library.

lochan-eda

An automated preprocessing pipeline that decides how to clean your data, not just that it should be cleaned.

Most EDA helpers apply the same fixed rule to every column — fill all NaNs with the mean, scale everything with StandardScaler. lochan-eda looks at each column's actual statistical shape — missingness, skew, cardinality, sparsity, outlier ratio — and picks the appropriate imputation, outlier, and scaling strategy for that column specifically. One call in, a model-ready DataFrame out.

from lochan_eda import AutomatedEDA

clean_df = AutomatedEDA(df).run_pipeline()

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Why

A real preprocessing pass usually means writing the same decision tree by hand, every time: is this column mostly missing? is it skewed or symmetric? does it have a handful of extreme values or a long tail? is it high-cardinality categorical? — before you can even decide how to impute, scale, or encode it.

lochan-eda encodes that decision tree in code. It's not a black box: every rule it applies is documented below, so you always know why a column was scaled with RobustScaler instead of StandardScaler, or why a category got grouped into "Other".

Features

• Adaptive missing-value imputation — different strategy for high-missingness, low-cardinality, and normally-distributed columns
• Adaptive outlier handling — trims, winsorizes, or transforms depending on how much of the column is actually affected
• Adaptive scaling — picks StandardScaler, RobustScaler, or MaxAbsScaler based on sparsity, skew, and outlier ratio
• Adaptive categorical encoding — binary mapping, one-hot, frequency, or target encoding based on cardinality
• Rare-category grouping — collapses low-frequency categories into "Other" before encoding
• One-call pipeline or granular per-step control — use AutomatedEDA end-to-end, or call HandleNumerical / HandleCategorical directly
• Built on pandas and scikit-learn — output is a plain DataFrame, drop it straight into any model

Installation

pip install lochan-eda

Quickstart

import pandas as pd
from lochan_eda import AutomatedEDA

df = pd.read_csv("your_data.csv")

eda = AutomatedEDA(df)
clean_df = eda.run_pipeline()

run_pipeline() runs the full sequence — impute, handle outliers, scale numerical columns; impute, group rare categories, encode categorical columns — and returns a single combined DataFrame with no missing values, aligned on index.

Verified example

Run against the 1,000-row test fixture shipped in this repo (tests/test_dataset.csv, 6 numerical + 7 categorical columns with injected missing values, outliers, and rare categories):

>>> df.shape
(1000, 13)
>>> df.isna().sum().sort_values(ascending=False).head(4)
num_drop       450
cat_drop       450
cat_unknown    200
cat_mode        50

>>> clean_df = AutomatedEDA(df).run_pipeline()
>>> clean_df.shape
(938, 13)
>>> clean_df.isna().sum().sum()
0
>>> list(clean_df.columns)
['num_cat_like', 'num_skewed', 'num_normal', 'num_sparse', 'num_outliers',
 'cat_mode', 'cat_unknown', 'cat_rare', 'cat_binary',
 'cat_ohe_Blue', 'cat_ohe_Green', 'cat_ohe_Red', 'cat_freq_Freq']

The two >40%-missing columns (num_drop, cat_drop) were dropped, every remaining missing value was imputed, 62 outlier rows were trimmed from num_outliers, and cat_ohe was one-hot encoded — with zero manual decisions.

How it decides

Numerical columns (HandleNumerical)

Step	Condition	Action
Imputation	>40% missing	Column dropped
	Uniqueness < 1% of rows (categorical-like numeric)	Mode imputation
	0–40% missing, |skew| < 0.5	Mean imputation
	0–40% missing, |skew| ≥ 0.5	Median imputation
Outliers (IQR method)	Outlier share ≤ 3%	Rows trimmed
	Outlier share > 3%, spiked tail	Winsorized at 5th/95th percentile
	Outlier share > 3%, long tail, contains zeros	Square-root transform
	Outlier share > 3%, long tail, no zeros/negatives	Log1p transform
Scaling	Sparsity ≥ 50% zeros	MaxAbsScaler
	Skew > 1.0, non-negative	Log1p transform + StandardScaler
	Outlier ratio ≥ 5%	RobustScaler
	Otherwise	StandardScaler

Categorical columns (HandleCategorical)

Step	Condition	Action
Imputation	>40% missing	Column dropped
	>10–40% missing	Filled with "Unknown"
	≤10% missing	Mode imputation
Rare grouping	Category frequency < threshold (default 5%)	Grouped into "Other"
Encoding	≤2 unique values	Binary integer mapping
	3–10 unique values	One-hot encoding
	>10 unique values, target provided	Target encoding
	>10 unique values, no target	Frequency encoding

API reference

Class / method	Description
AutomatedEDA(df)	Orchestrates the full pipeline
.run_pipeline()	Runs numerical + categorical handling end-to-end, returns one combined DataFrame
HandleNumerical(df)	Isolates numeric columns for standalone use
.num_imputer(exclude=None)	Missing-value imputation only
.outlier_manager(exclude=None)	Outlier handling only
.scaler(exclude=None)	Scaling only
.full_handler()	Imputer → outlier manager → scaler, in order
HandleCategorical(df)	Isolates categorical columns for standalone use
.cat_imputer()	Missing-value imputation only
.rare_manager(threshold=0.05)	Rare-category grouping only
.encoder(target=None)	Encoding only; pass target to enable target encoding on high-cardinality columns
.full_handler()	Imputer → rare manager → encoder, in order

Every numerical method takes an optional exclude (str or list) to skip specific columns — useful for keeping an ID column or a pre-engineered feature untouched.

Using components individually

from lochan_eda import HandleNumerical, HandleCategorical

num = HandleNumerical(df)
num.num_imputer(exclude="customer_id")
num.outlier_manager()
scaled_df = num.scaler()

cat = HandleCategorical(df)
cat.cat_imputer()
cat.rare_manager(threshold=0.02)
encoded_df = cat.encoder(target=df["churned"])

Testing

git clone https://github.com/LochanJangid/lochan-eda.git
cd lochan-eda
pip install -e .
pip install pytest
pytest -v

Contributing

Issues and PRs are welcome. Please run pytest before submitting a pull request.

License

MIT © Lochan Jangid

Author

Lochan Jangid GitHub: @LochanJangid