[ENH] in notebooks, replace yfinance download with loaders

[tschm]

Get rid of yfinance. Create on csv file serving all notebooks

[tschm]

@fkiraly this is good to be merged. Now using one flat file common for all notebooks. I have added the script to generate this file.

[fkiraly]

Great! I really think we need to replace downloads by onboard data.

• I believe you have to explicitly request csv to be packaged in pyproject, or users will not be able to load the data. This becomes apparent in the wheels/release test (but we are not running a packaging test regularly).
• could you do separate things in separate PR? E.g., linting the notebooks, changing dependencies, etc.
• The pattern that I would use is adding a load_datasetname function instead of directly loading a csv. That makes the notebook easier to read.

Different topic, I think the pip installs should be removed from the notebooks, this messes up the VM that tests the notebooks.

[fkiraly]

Plus, could you please, please write descriptive summaries for your PR? Use AI if you need to.

[tschm]

I don't understand. Do you want to include the notebooks in the package released?

[tschm]

import os
if not os.path.isdir('data'):
    os.system('git clone https://github.com/pyportfolio/pyportfolioopt.git')
    os.chdir('PyPortfolioOpt/cookbook')

??? why would one have this in a notebook?

[fkiraly]

I don't understand. Do you want to include the notebooks in the package released?

no, I want loader functions for the csv in the package release, and the notebooks then import the loader from the package, rather than loading the csv directly.

from pypfopt.data import load_something

my_dummydata = load_something()

All the csv manipulation is hidden underneath, ensuring that the notebook is short and does not distract from what is being shown.