NumPy

NumPy is the bedrock of the Python ecosystem. v2.0 (2024) brought the first major ABI change in 15 years, improving performance and API consistency.

When to Use

• Linear Algebra: Matrix multiplication, eigenvalues.
• Array Manipulation: Reshaping, broadcasting.
• Foundation: When building libraries (like PyTorch or Pandas).

Core Concepts

Broadcasting

The magic rule that allows array(3x1) + array(3) to work.

Dtypes

Precision matters. float32 vs float64.