Production Data Engineering: Pandas Vectorization & Missing Data Imputation
Learning Objective: Optimize Pandas DataFrame operations using vectorization over .apply() loops and handle missing data using domain-specific imputations.
- Intuition & Big Picture
Pandas DataFrames are backed by C-contiguous NumPy array buffers. Operating vectorized mathematical primitives allows CPU SIMD instruction sets to execute batch calculations at maximum C speeds.
Anil's Insight: Avoid iterating row-by-row with iterrows()! It is up to 500x slower than vectorized operations because iterrows() creates a new pd.Series object for every single row!