Clean a CSV in Python

Why it matters

80 percent of analyst work is cleaning. A tidy notebook is the most trusted proof of work.

Steps

• Load the CSV and log info, dtypes, and row counts
• Tidy column names (lowercase, no spaces)
• Handle missing values with written reasoning per column
• Drop duplicates and fix date and number formats
• Export cleaned.csv and log every decision

Expected output

Notebook plus cleaned.csv plus decision log

Checklist

• Zero duplicates remain
• All dtypes correct
• Missing values documented
• Script re-runnable from scratch

Evidence

Notebook link plus cleaned.csv

Self review

Could someone else reproduce your clean file from raw data without asking?