PHP Arrays, ordered or not? - php

Question

I have an Array of product types in PHP, it looks pretty much like this:
$types = [
0 => "cars",
1 => "motorbikes",
2 => "boats",
3 => "airplanes"
];
So that when then user wants to get or save it, I can use the ID of the category to insert or get it from the database, like this:
select * from items where type = 0;
now, My doubt is the following: if I am using integer index keys, would it not be the same to use the following?
$types = ["cars", "motorbikes", "etc."];
Since PHP will give an integer auto-ordering.
Which one would you consider to be best practice in this case? The advantage of the first example seems to only be the fact that I can assign different keys, like for private categories or such, but I don't know really.
It is also important to consider that the values will need to be translated so, should I consider even just using IDs? like
$types = ["t1", "t2", "etc."];
and then insert the translation somewhere else?

Answer 1

There are 2 possible options.
Your current option 1 with manually set indexes.
A way better one - a table in the DB, holding these categories, which allow editing categories without losing the association between keys and names.
Your current option 2 is not an option at all - it will break the order the same moment you insert or delete a category
Here you set the index:
$types = [
3 => "airplanes"
index ^ ^ value
So, if you delete cars from the list, the index remain associated with it's value:
$types = [
1 => "motorbikes",
2 => "boats",
3 => "airplanes"
];
While if you don't set indexes manually
$types = ["motorbikes", "boats", "airplanes"];
airplanes will lose it's association, and become boats. It's not ht magic we expect from the web application

Answer 2

It all depends on the project. If I'm working with an array of items from the database I like the key to be the id from the database so it's available should I need it. If there's no need for the ids then there is no need to define a key. It will start at 0 anyways.

Answer 3

I think your first approach is a good one. You could even do it as default translation:
$types["en"] = []
Of course if you have a default language variable, you can use it from the start, and it will be much easier in the future to translate it further and expand
The arrays will be seen as the same so you can order it and take key as ID but it's not the best practice, all depends on how you design your relationship between arrays, php and database.

Answer 4

I might be missing your question but the array in PHP is ordered hash map basically. So ["cars", "motorcycles", "etc."] is guaranteed to preserver ordering (and have keys 0, 1, 2). But you might instead consider do the following
class AutoTypes {
const TYPE_CAR = 0;
const TYPE_MOTORCYCLE = 1;
const TYPE_BOAT = 2;
public static function getLabels() {
return array(self::TYPE_CAR => 'Car', self::TYPE_MOTORCYCLE => 'Motorcycle', self::TYPE_BOAT => 'Boat');
}
}
This way you can refer to the auto type by AutoTypes::CONSTANT. Because if you want to remove motorcycle at some point, not using clear indexes in the array, removing an item will brake your logic.

Answer 5

In my opinion, in this circumstance it's better to use
$types = ["cars", "motorbikes", "etc."];
As you say, PHP automatically assigns integer indexes starting from 0; so there's no need to specify the index that it would be assigned anyway.
It's up to you however, if you feel that it isn't clear enough just to declare an array without specifying the indexes manually then that's up to you. But personally I feel that it's obvious to any competent programmer and so therefore it's a waste of time and hard disk space to manually specify those indexes.