Question

I’m creating a global file to hold items that will be re-used throughout my website. What are the differences between these two lines of code? Is one “better” than the other?

This:

$logo = "img/mainlogo.jpg";

vs this:

function logo() {
   echo "img/mainlogo.jpg";
}

Answer 1

Functions are good.

I see that function logo() is better than $logo. echo doesn’t take much memory, but $logo does. Even though, function logo() takes something, it will be handled by PHP’s very own garbage collector. You can also use these functions to ensure that you are not misusing the memory allocated.

1. memory_get_peak_usage();
2. memory_get_usage();

Explanation:

Upon the ending of an in use function PHP clears the memory it was using, at least more efficiently than if not using a function. If you are using recursive code or something similar that is memory intensive try putting the code into a function or method, upon closing of the function/method the memory used for the function will be garbaged much more efficiently than that of unsetting variables within the loop itself.

Source: 7 tips to prevent PHP running out of memory