PHP Conference Nagoya 2025

ArrayObject::offsetUnset

(PHP 5, PHP 7, PHP 8)

ArrayObject::offsetUnset指定したインデックスの値を解除する

説明

public ArrayObject::offsetUnset(mixed $key): void

指定したインデックスの値を解除します。

パラメータ

key

解除したいインデックス。

戻り値

値を返しません。

例1 ArrayObject::offsetUnset() の例

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

上の例の出力は以下となります。

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

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User Contributed Notes 2 notes

up
3
pvenakis at efront dot gr
16 years ago
When traversing recursively nested arrays using an RecursiveIteratorIterator, you cannot offsetUnset() or offsetSet() sub-array values, unless they are *all* declared as ArrayObject.
up
0
oalexandrino at yahoo dot com dot br
17 years ago
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) ;

?>
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