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PHP Array Functions and C Syntax Loop Methods Few People Even Know.
Note, sorry but this article is going to skip between languages a bit.
Everyone knows about count, for and foreach. They’re the staple of programming array loops. If you work in PHP, you likely know what they do and how to use them…
But what aboutcurrent, end, key, last, next, prev, and reset?
Much less how if/do/while can be used to smartly make loops in most all C syntax languages?
I’ve been shocked the past year or so how many dev’s I come across who’ve never even heard of them, much less understand their use. What prompted this article is that I was just working on a “function stack” of anonymous that other processes can add to, and I used this because of the “You can’t add to an array inside a foreach” issue; and a colleague saw it and said “what the devil is that?!?” Actually he used a bit stronger language when he saw the do/while.
They are an alternative way of going through an array — and in some cases objects — based on the simple fact that:
PHP Array’s… Aren’t.
That might sound odd, but from the perspective of an assembly language, C, or Pascal/ADA developer like myself, it’s true. PHP fakes the APPEARANCE of arrays just like JavaScript does.
So if PHP Array’s aren’t actually arrays, what are they? The answer: Pointered Lists!
The container object (we can’t normally access) has a pointer to the first and last elements, and each element has a pointer to its previous and next siblings. In the case of all of those pointers null (or boolean false) implies that there isn’t one.
Instead of the “true array’ approach of every value being in a orthogonal fixed size one after the other in memory, they can be all over memory because of the need for each element to have a dynamic size. Why is that needed? Because PHP array elements can be anything; string, integer, float — even in the same “array”. “real” arrays rely on the data being a uniform size, something dynamically typed languages like PHP and JavaScript aren’t designed around.
If that sounds familiar, it’s quite similar to walking the DOM or working with binary trees. It’s just that in…
