P87PandasBeginnerImplement8 min
Implement Group-Level Normalization With Pandas Transform
Normalize values relative to each row's group while preserving the original DataFrame shape.
#implement#groupby#transform
Scenario
A sales table has one row per representative and needs each sale expressed relative to that representative's region average.
Problem statement
Implement the group-level normalization and explain why `transform` is appropriate.
Your Task
- Compute a region-level mean aligned to each row.
- Create the normalized value.
- Explain why aggregation alone is insufficient.
Input
df = pd.DataFrame({'region': ['East', 'East', 'West'], 'sales': [100, 140, 90]})Related Concepts
Pandas groupbyTransformData grain
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