NumPy

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.

Stride Tricks

Efficient memory views without copying data.

Best Practices (2025)

Do:

• Check v2.0 compat: Many old libraries broke with NumPy 2.0.
• Use numpy.strings: New string kernels in v2.0 are much faster.

Don't:

• Don't write for loops: Always vectorize operations.

References

• NumPy Documentation