[0.1.0] Intro NDArryLoader

[Wh1isper]

Description

Motivation and Context

• Introduce the NDArrayLoader for lazy reading of columnarly stored ndarry
• Update docstring and examples

How has this been tested?

Types of changes

• Maintenance (no change in code, maintain the project's CI, docs, etc.)
• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)

Checklist:

• My code follows the code style of this project.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.

[sweep-ai]

Apply Sweep Rules to your PR?

• Apply: All new business logic should have corresponding unit tests.
• Apply: Refactor large functions to be more modular.
• Apply: Add docstrings to all functions and file headers.

[Wh1isper]

@MooooCat
Please review the code first, I'm adding documentation.

[MooooCat]

@MooooCat Please review the code first, I'm adding documentation.

Sure.

[Wh1isper]

Will update user guide before official release

[MooooCat]

I have a question about the NDArray Loader.

I noticed that it names the .npy in order.

(I'm not sure if this will happen yet) When multiple data loaders run at the same time using default parameters (that is, the same cache_dir), this sequential naming method may cause conflicts:

NDArrayLoader 1 stores 1.npy ，then NDArrayLoader 2 store another Array, named 1.npy, on same ndarry_cache dir.

In the naming of cached .npy files, if the path contains an id field, there will be no such concern. Also, suggesting developers to use different cache paths is obviously a right approach.

Could this be a problem?

[Wh1isper]

@MooooCat Yes, different NDArrayLoader should use different subdirs. I'll draft a PR fot it