# Data Cleaning

> Data cleaning, preprocessing, and quality assurance techniques

- Skill: `majiayu000/data-cleaning` (Agent Skill, multi-file: 2 files)
- Install (CLI): `npx skillmds add majiayu000/data-cleaning`
- Raw SKILL.md: https://api.skillmd.com/api/skills/majiayu000/data-cleaning/raw
- Safety review: pending
- Works with: Claude Code, Claude.ai, OpenAI Codex
- Category: Coding & Dev Tools
- Author: majiayu000 (https://skillmd.com/u/majiayu000)
- Updated: 2026-09-09
- Page: https://skillmd.com/skills/majiayu000/data-cleaning

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# Data Cleaning Skill

## Overview
Master data cleaning and preprocessing techniques essential for reliable analytics.

## Topics Covered
- Missing value handling (imputation, deletion)
- Outlier detection and treatment
- Data type conversion and validation
- Duplicate identification and removal
- String cleaning and normalization

## Learning Outcomes
- Clean messy datasets
- Handle missing data appropriately
- Detect and treat outliers
- Ensure data quality

## Error Handling

| Error Type | Cause | Recovery |
|------------|-------|----------|
| Memory error | Dataset too large | Use chunking or sampling |
| Type conversion failed | Invalid data format | Apply preprocessing first |
| Encoding issues | Wrong character encoding | Detect and specify encoding |
| Validation failure | Data doesn't meet schema | Review and adjust validation rules |

## Related Skills
- programming (for automation)
- foundations (for data quality concepts)
- databases-sql (for SQL-based cleaning)