8. Analysis Patterns

1. Aggregation

The Split-Apply-Combine strategy.

1. Split: Break data into groups (e.g., by 'Sector').
2. Apply: Compute a function (e.g., 'mean').
3. Combine: Glue it back together.

python
df.groupby('Sector')['Revenue'].agg(['mean', 'max'])

2. Merging

Joining datasets like SQL.

python
# Inner Join (Default)
pd.merge(users, orders, on='user_id')