How to create an Empty Set in PHP - Step by Step Examples

How to create an Empty Set in PHP ?

Answer

To create an empty set in PHP, you can use the SplObjectStorage class, which is the closest equivalent to a set data structure in PHP.


✐ Examples

1 Create an Empty Set Using SplObjectStorage

In this example,

  1. We use the SplObjectStorage class which is a built-in class in PHP that allows you to create a collection of objects, behaving similarly to a set.
  2. We create an instance of the SplObjectStorage class by calling its constructor with no arguments.
  3. We declare a variable named $set1 and assign it the result of calling the new SplObjectStorage() constructor.
  4. The new SplObjectStorage() constructor creates a new, empty set-like storage.
  5. We then print the $set1 using the var_dump function to verify its contents.

PHP Program

<?php
$set1 = new SplObjectStorage();
var_dump($set1);
?>

Output

object(SplObjectStorage)#1 (0) {
}

2 Create an Empty Set and Add Elements

In this example,

  1. We create an instance of the SplObjectStorage class to serve as our set by calling the new SplObjectStorage() constructor.
  2. We declare a variable named $set2 and assign it the result of the new SplObjectStorage() constructor.
  3. We create some objects to add to the set. For example, we create objects of the standard class stdClass and assign properties to them.
  4. We add these objects to $set2 using the attach method of the SplObjectStorage class.
  5. We then print the $set2 using the var_dump function to verify its contents.

PHP Program

<?php
$set2 = new SplObjectStorage();

$object1 = new stdClass();
$object1->name = 'apple';
$set2->attach($object1);

$object2 = new stdClass();
$object2->name = 'banana';
$set2->attach($object2);

var_dump($set2);
?>

Output

object(SplObjectStorage)#1 (2) {
  [0]=> object(stdClass)#2 (1) {
    ["name"]=> string(5) "apple"
  }
  [1]=> object(stdClass)#3 (1) {
    ["name"]=> string(6) "banana"
  }
}

Summary

In this tutorial, we learned How to create an Empty Set in PHP language with well detailed examples.


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