Lesson 6.8: Review & Rehearse – Data Debugging and Practice

Today’s Goals

• Review Unit 6 concepts (datasets, cleaning, filtering, sorting, nested data)
• Practice debugging real dataset code
• Prepare for the Unit 6 Exam

Warm-Up Question

• Which Unit 6 skill do you feel most confident about? Which needs more practice?

Review Topics

• Lists & dictionaries for datasets
• Cleaning data (dropna, drop_duplicates, astype)
• Filtering and sorting with pandas
• Aggregations: mean, median, std
• Nested data structures
• Debugging errors (IndexError, ValueError, FileNotFoundError)

Buggy Code Example

import pandas as pd

data = {
    'name': ['Alice', 'Bob', 'Charlie'],
    'score': [90, 'eighty', 85]
}

df = pd.DataFrame(data)
print(df['score'].mean())   #  Error here

Fixing the Bug

df['score'] = pd.to_numeric(df['score'], errors='coerce')
print(df['score'].mean())

Class Activity

• Work in pairs on buggy dataset scripts
• Fix as many as you can in 25 minutes
• Record what the bug was and how you fixed it

Student Challenge

• Complete a mini-project using your chosen dataset:
  • Clean the dataset
  • Perform filtering, sorting, aggregation
  • Create at least one visualization

Wrap-Up

• Debugging practice makes you faster at problem solving
• Next time: Unit 6 Exam