DataLint

Automated data validation for ML teams
Find data quality issues before they break your models.

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Overview

DataLint learns from clean datasets to automatically validate new data and prevent ML training failures. It catches the data quality issues that cause 60% of ML project failures before they break your models.

Key Features

Feature	Description
Zero Configuration	Works out of the box with sensible defaults
ML-Focused	Optimized specifically for model training data quality
Learn from Data	Automatically generates validation rules from clean datasets
Schema Drift Detection	Catches when production data differs from training data
CI/CD Ready	JSON output for integration with automated pipelines

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Installation

pip install datalint

Requirements: Python 3.8+

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Quick Start

Validate a Dataset

datalint validate mydata.csv

Output:

Loaded dataset: 150 rows x 5 columns

  missing_values: No missing values found
  data_types: Data types appear consistent
  outliers: Outlier levels appear normal
  correlations: Found 1 highly correlated feature pairs
  constant_columns: Found 1 columns with constant values

Summary: 3 passed, 1 warnings, 1 failed
Tip: Address failed checks before training ML models

Learn from Clean Data

# Create a validation profile from your training data
datalint profile training_data.csv --learn

# Validate new data against the learned profile
datalint profile new_data.csv --profile training_data_profile.json

Export for CI/CD

datalint validate data.csv --format json --output results.json

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What It Checks

DataLint performs five core validation checks:

1. Missing Values

Identifies columns with excessive null values that will crash or degrade ML models.

# Example: 43% missing values in 'age' column
# Recommendation: Impute or remove before training

2. Data Type Consistency

Detects mixed types (e.g., numbers and text in the same column) that cause parsing errors.

# Example: price column has [10.99, 25.50, 'FREE', 15.00]
# Recommendation: Convert to consistent type

3. Outlier Detection

Uses the IQR (Interquartile Range) method to find statistical anomalies that can dominate model training.

# Example: salary column has values [50k, 55k, 48k, 5M]
# Recommendation: Investigate or cap extreme values

4. High Correlations

Finds feature pairs with >95% correlation that provide redundant information.

# Example: height_cm and height_inches are 100% correlated
# Recommendation: Remove one redundant feature

5. Constant Columns

Detects columns with zero variance that provide no predictive information.

# Example: 'country' column is 'USA' for all rows
# Recommendation: Remove before training

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Comparison with Other Tools

Feature	DataLint	Great Expectations	Pandera	Deequ
Zero config	Yes	No (YAML required)	No (schema required)	No
Auto-learn rules	Yes	No	No	Partial
ML-focused	Yes	General	General	General
Setup time	5 minutes	Hours/Days	Hours	Hours
Pricing	Free	Free	Free	Free (AWS)

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Architecture

datalint/
├── cli.py              # Command-line interface
├── engine/
│   ├── validators.py   # Core validation checks
│   ├── learner.py      # Rule learning from clean data
│   └── profiler.py     # Statistical profiling
└── utils/
    ├── io.py           # File loading (CSV, Excel, Parquet)
    └── reporting.py    # Output formatter (text, JSON, HTML)

Architecture Diagrams

Class Diagram

Shows the class hierarchy and relationships

classDiagram
    class BaseValidator {
        <<abstract>>
        +String name*
        +ValidationResult validate(DataFrame df)*
        +String __repr__()
    }

    class Formatter {
        <<abstract>>
        +String format(List~ValidationResult~ results)*
    }

    class ValidationResult {
        +String name
        +String status
        +String message
        +List issues
        +List recommendations
        +Dict details
        +Boolean passed
        +Dict to_dict()
    }

    class ValidationRunner {
        -List~BaseValidator~ validators
        +ValidationRunner(List~BaseValidator~ validators)
        +void add_validator(BaseValidator validator)
        +List~ValidationResult~ run(DataFrame df)
        +Dict~String,ValidationResult~ run_dict(DataFrame df)
    }

    class ConcreteValidator {
        +String name
        +ValidationResult validate(DataFrame df)
    }

    class ConcreteFormatter {
        +String format(List~ValidationResult~ results)
    }

    BaseValidator <|.. ConcreteValidator : implements
    Formatter <|.. ConcreteFormatter : implements
    ValidationRunner --> BaseValidator : uses
    BaseValidator --> ValidationResult : returns
    ConcreteValidator --> ValidationResult : returns

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Interface Diagram

Shows key interfaces and abstraction contracts

classDiagram
    class BaseValidator {
        <<abstract>>
        +name: str*
        +validate(df: DataFrame): ValidationResult*
    }

    class Formatter {
        <<abstract>>
        +format(results: List[ValidationResult]): str*
    }

    class ValidationResult {
        +name: str
        +status: Literal['passed', 'warning', 'failed']
        +message: str
        +issues: List
        +recommendations: List
        +details: Dict
        +passed: bool
        +to_dict(): Dict
    }

    class ValidationRunner {
        -validators: List[BaseValidator]
        +__init__(validators=None)
        +add_validator(validator: BaseValidator)
        +run(df: DataFrame): List[ValidationResult]
        +run_dict(df: DataFrame): Dict[str, ValidationResult]
    }

    BaseValidator <|.. ConcreteValidator : implements
    Formatter <|.. ConcreteFormatter : implements
    ValidationRunner --> BaseValidator : uses
    BaseValidator --> ValidationResult : returns

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Component Diagram

Illustrates high-level software components

graph TD
    CLI[Command Line Interface]
    ENG[Core Validation Engine] 
    UTI[Utility Functions]

    CLI --> ENG
    CLI --> UTI
    ENG --> UTI

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Deployment Diagram

Shows how the system is deployed

graph TD
    subgraph Local[Local Machine]
        Python[Python Environment]
        DataLint[DataLint Package]
    end
    Data[Data Files]
    Reports[Output Reports]

    DataLint --> Data
    DataLint --> Reports
    Python --> DataLint

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Sequence Diagram

Displays the validation workflow sequence

sequenceDiagram
    participant U as User
    participant C as CLI
    participant V as ValidationRunner
    participant B as BaseValidator
    participant D as DataFrame

    U->>C: datalint validate file.csv
    C->>V: run(df)
    loop for each validator
        V->>B: validate(df)
        B->>D: analyze data
        D-->>B: return analysis
        B-->>V: ValidationResult
    end
    V-->>C: results list
    C-->>U: formatted output

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Activity Diagram

Shows the validation pipeline activities

flowchart TD
    Start([Start])
    Run[User runs datalint validate]
    Parse[Parse command line arguments]
    Load[Load data file]
    Check{File loaded successfully?}
    Init[Initialize ValidationRunner]
    Validate[Run all validators]
    CheckResult{Validation passed?}
    Success[Generate success report]
    Fail[Generate failure report]
    Recomm[Show recommendations]
    Error[Show error message]
    Exit([Exit])

    Start --> Run
    Run --> Parse
    Parse --> Load
    Load --> Check
    Check -->|Yes| Init
    Init --> Validate
    Validate --> CheckResult
    CheckResult -->|Yes| Success
    CheckResult -->|No| Fail
    Fail --> Recomm
    Success --> Exit
    Recomm --> Exit
    Check -->|No| Error
    Error --> Exit

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Use Case Diagram

Illustrates user interactions with the system

flowchart LR
    DS([Data Scientist])
    MLE([ML Engineer])
    DevOps([DevOps Engineer])

    UC1[Validate Dataset]
    UC2[Learn from Clean Data]
    UC3[Profile Data Quality]
    UC4[Generate Reports]
    UC5[CI/CD Integration]

    DS --> UC1
    DS --> UC2
    MLE --> UC3
    DevOps --> UC5
    UC1 --> UC4
    UC2 --> UC4
    UC3 --> UC4

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Roadmap

• Phase 1: Core validation engine with CLI
• Phase 2: Learning system (auto-generate rules from clean data)
• Phase 3: HTML reports + GitHub Actions integration
• Phase 4: Web dashboard + team collaboration

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Contributing

DataLint is in active development. We welcome contributions:

• Bug Reports: Open an issue with reproduction steps
• Feature Requests: Describe your use case
• Pull Requests: See CONTRIBUTING.md for guidelines
• Feedback: Share your experience using DataLint

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License

MIT License - see LICENSE for details.

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DataLint - Because good models start with good data.