If you're looking to improve your PHP, it makes sense to focus on learning the features of the language that are most commonly used.
Well I ran some searches on the OpenCart source code to help identify the most important PHP functions to learn to help you develop OpenCart sites:
https://www.antropy.co.uk/blog/efficien ... evelopers/
For quick, professional OpenCart support please email firstname.lastname@example.org
The most generated errors being found on Opencart forum originates from contributed programming. The increased counters are caused by posted redundancies of the same solutions that were already provided prior.