Numerical-Analysis-Examples
github.com
github.com
Because one thing I'd miss in the examples would be a few lines of comments - if they're meant to be illustrative of a book that's ok, but learning the other way (looking at source code, structure and comments) is also a good way for many people to understand. If you're well read in source code, you can read it to understand the math better.
That said, for actually getting the job done, you would probably use a library like numpy instead of a library like this, as it is more powerful, both in terms of execution speed and speed of development.
Each contribution is small and modular, so you don't have to learn several thousand lines of code.
The "real world" knowledge you have to learn is pretty specific and easy to convert into code (compared to, say, legal opinions or object recognition).