SplFixedArray::offsetUnset

(PHP 5 >= 5.3.0, PHP 7, PHP 8)

SplFixedArray::offsetUnset — Unsets the value at the specified $index

Description

public SplFixedArray::offsetUnset(int $index): void

Unsets the value at the specified index.

Parameters

index: The index being unset.

Return Values

No value is returned.

Errors/Exceptions

Throws RuntimeException when index is outside the defined size of the array or when index cannot be parsed as an integer.

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User Contributed Notes 1 note

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c dot 1 at smithies dot org ¶

14 years ago

This function assigns NULL to the array element. Its use has no effect on count(). Whereas assigning NULL to an element will have no effect on isset(), offsetUnset() and unset() do. Whereas unsetting an element affects the behaviour of foreach() as applied to an array or an ArrayObject, it has no such effect on SplFixedArray, as demonstrated by the code below.



<?php



class atest extends SplFixedArray {

  public function fill() {

    for ($i = $this->count(); --$i >= 0; ) $this[$i] = $i;

  }

  public function dump() {

    $sep = ' ';

    foreach ($this as $k => $v) {

      echo $sep, "$k: ", (is_null($v) ? 'NULL' : $v);

      if (!isset($this[$k])) echo ' and unset';

      $sep = ', ';

    }

    echo PHP_EOL;

  }

}



$a = new atest(3);

$a->dump(); //  0: NULL and unset, 1: NULL and unset, 2: NULL and unset

$a->fill();

$a->dump(); //  0: 0, 1: 1, 2: 2

$a[1] = NULL;

unset($a[2]);

$a->dump(); //  0: 0, 1: NULL, 2: NULL and unset

?>

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