There comes a time in the life of a serious software engineer when he wants to implement a custom programming language. Not with the goal of creating a language that gains widespread adoption (there are enough programming languages already), but as an exercise to gain deeper insight into how programming languages work.
In the previous post we examined the potential performance issues with nested for-loops and how they can be improved using array lookups instead. Another common pitfall in terms of performance can be sorting when done incorrectly which we will examine here.
One of the most common issues that I see almost daily when reviewing code is nested loops where they aren't required. They are particularly tricky because they are not slow with small data sets (which developers often use for testing), but become slow in production environment where data sets are larger. Of course, testing with too small data sets is a separate problem which should be fixed as well.
On this post I would like to introduce some generic utility functions for PHP. I often keep these in the global namespace because they are so useful. You may wish to wrap them in a namespace, or even a class, depending on your use case. They follow similar naming convention as the built-in functions of PHP because I view them almost like extensions to the standard library.
Have you ever encountered a situation where the performance of your PHP script is not great, but you are not sure where the problem is? Then you try to guess and change some part blindly just to see if that would help?