| What you want | What actually works best | | --- | --- | | One free PDF | GitHub repo + PHP manual + curated blog posts | | PHP 5 examples | PHP 7.4+ typed properties and return types | | Static download | Interactive learning with php -a (interactive shell) |
When looking for the in a free PDF, you must ensure the book or guide is updated for PHP 7+. A resource written for PHP 5.3 will contain deprecated features (e.g., create_function() instead of closures) and miss out on performance optimizations.
provide comprehensive, open-source documentation on these concepts for free. O'Reilly Media Alternative "Best Works"