ArrayIterator::offsetUnset

(PHP 5, PHP 7, PHP 8)

ArrayIterator::offsetUnset — Unset value for an offset

说明

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

Unsets a value for an offset.

If iteration is in progress, and ArrayIterator::offsetUnset() is used to unset the current index of iteration, the iteration position will be advanced to the next index. Since the iteration position is also advanced at the end of a foreach loop body, use of ArrayIterator::offsetUnset() inside a foreach loop may result in indices being skipped.

参数

key

The offset to unset.

返回值

没有返回值。

参见

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User Contributed Notes 3 notes

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2
rkos...
8 years ago
This is my solution for problem with offsetUnset
<?php

$a = new ArrayObject( range( 0,9 ) );
$b = new ArrayIterator( $a );

for ( $b->rewind(); $b->valid();  )
{
    echo "#{$b->key()} - {$b->current()} - <br>\r\n";
    if($b->key()==0 || $b->key()==1){
        $b->offsetUnset( $b->key() );
    }else {
        $b->next();
    }
}

var_dump($b);
?>
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2
olav at fwt dot no
10 years ago
When unsetting elements as you go it will not remove the second index of the Array being worked on. Im not sure exactly why but there is some speculations that when calling unsetOffset(); it resets the pointer aswell.

<?php

$a = new ArrayObject( range( 0,9 ) );
$b = new ArrayIterator( $a );

for ( $b->rewind(); $b->valid(); $b->next() )
{
    echo "#{$b->key()} - {$b->current()} - \r\n";
    $b->offsetUnset( $b->key() );
}

?>

To avoid this bug you can call offsetUnset in the for loop

<?php
/*** ... ***/
for ( $b->rewind(); $b->valid(); $b->offsetUnset( $b->key() ) )
{
/*** ... ***/
?>

Or unset it directly in the ArrayObject
<?php
/*** ... ***/
    $a->offsetUnset( $b->key() );
/*** ... ***/
?>

which will produce correct results
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0
Adil Baig @ AIdezigns
10 years ago
Make sure you use this function to unset a value. You can't access this iterator's values as an array. Ex:

<?php
$iterator = new \RecursiveIteratorIterator(new \RecursiveArrayIterator($arr));

foreach($iterator as $key => $value)
{
    unset($iterator[$key]);
}
?>

Will return :

PHP Fatal error:  Cannot use object of type RecursiveIteratorIterator as array

offsetUnset works properly even when removing items from nested arrays.
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