PHP: ArrayObject::offsetUnset - Manual

Example #1 ArrayObject::offsetUnset() example

<?php
$arrayobj = new ArrayObject(array(0=>'zero',2=>'two'));
$arrayobj->offsetUnset(2);
var_dump($arrayobj);
?>

The above example will output:

object(ArrayObject)#1 (1) {
  ["storage":"ArrayObject":private]=>
  array(1) {
    [0]=>
    string(4) "zero"
  }
}

When traversing recursively nested arrays using an RecursiveIteratorIterator, you cannot offsetUnset() or offsetSet() sub-array values, unless they are *all* declared as ArrayObject.

Be careful when you are working with collections. This method works with the reference of an array instead of its retrieved value.

So, you can do a mistake.

In order to understand have a look at code as follow:

<?php
class Employee
{
    public function __construct()
    {
    }    
}

class Company
{
    private $arrEmployee;
    
    public function __construct()
    {
    }    
    
    public function AddEmployee(Employee $oEmployee)
    {
        $this->arrEmployee[] = $oEmployee;    
    
    }
    
    public function getEmployeeList()
    {
        return $this->arrEmployee;
            
    }
    
} 
?>

<?php

// first, creates the Company object
$oCompany = new Company();

// second, add 10 elements in
foreach( range(0, 9) as $index )
{
    $oCompany->AddEmployee( new Employee() );
}

// get them
$arrEmployee = $oCompany->getEmployeeList();

// creates an ArrayObject from "$arrEmployee"
$arrayobject = new ArrayObject($arrEmployee);

// unsets its firt five elements
foreach( range(0, 4) as $index )
{
    $arrayobject->offsetUnset($index);
} 

// get them again
$arrEmployee = $oCompany->getEmployeeList();

// it shows just 5 elements, they were removed as reference via "offsetUnset" method
print_r($arrEmployee) ;

?>