HashSet in php

[AzeS]

I am trying to imitate the hashset function of Visual Basic. For this of course, I must declare a variable globally and here it begins to fail already; I have tried it without the interpreter global but also here it does not work at all.You might have better suggestions as I could immit, or even improvements for the code?

I look forward to answers and suggestions for improvement.

<?php 
/**
* 
*/
global $Hashset = array();
class stimpackZ
{


	public function hash_add($NAME,$DATA) {
		
			
		if ($NAME = 0) {
			$name_of_hash = count($Hashset) + 1;
			global $Hashset[$name_of_hash] = $DATA;
			echo $name_of_hash;
			return 1;
		} else {
			$name_of_hash = $NAME;
			$Hashset[$name_of_hash] = $DATA;
			return 1;
		}

		

	}
	public function hash_create($NAME) {

	}

	
	public function hash_get() {
		return $Hashset;
	}
	public function hash_cls() {
		global $Hashset = null;
		global $Hashset = array();
		return 1;
	}
	public function hash_del($ARG,$DATA) {
		switch ($ARG) {
			case 0:
				$key = array_search($DATA, global $Hashset);
				unset(global $Hashset[$key]);
				return 1;
				break;
			case 1:
			unset(global $Hashset[$DATA]);
				return 1;
				break;
			default:
				return 0;
				break;
		}
		
	}
	public function hash_test() {
		var_dump(global $Hashset);
	}
}

?>

 

[Jacques1]

The code makes no sense. It's generally a bad idea to imitate other languages. Instead, you should specifiy the goal and then implement it with the features of your current language.

 

So what is the goal? A mathematical set which can contain a value exactly once? Then the right implementation is an associative array where the keys are the set elements and the values are arbitrary:

<?php

$set = [];

// store 42 (the value is irrelevant)
$set[42] = true;

// store 42 again (this has no effect, just like you would expect from a set)
$set[42] = true;

// check if the set contains certain elements
$contains_42 = isset($set[42]);
$contains_43 = isset($set[43]);

var_dump($contains_42, $contains_43);

// delete element
unset($set[42]);

$contains_42 = isset($set[42]);

var_dump($contains_42);

Putting this into a class shouldn't be too hard now. I'm sure there are also existing libraries.

<?php

class Set
{
    private $elements = [];

    public function add($element)
    {
        $this->elements[$element] = true;
    }

    public function remove($element)
    {
        unset($this->elements[$element]);
    }

    public function contains($element)
    {
        return isset($this->elements[$element]);
    }
}

$set = new Set();

$set->add(42);
$set->add(42);

var_dump($set->contains(42));
var_dump($set->contains(43));

$set->remove(42);

var_dump($set->contains(42));

Edited January 17, 2017 by Jacques1

[AzeS]

Thanks for this helpful answer, I will immediately try to imply this and post the result at completion. I leave the thread open if further suggestions are present. 
Thanks Jacques. 

[Jacques1]

Note that associative arrays have a couple of quirks which can lead to confusing behavior. Depending on the exact type of the elements (strings? floats? objects?), you may need a different implementation. The above works best for integers and strings.

Edited January 17, 2017 by Jacques1