ArrayIterator::offsetUnset()

(PHP 5,PHP 7)

Unset value for an offset

说明

publicArrayIterator::offsetUnset(mixed $index) : void

Unsets a value for an offset.

Warning

本函数还未编写文档，仅有参数列表。

参数

$index

The offset to unset.

返回值

没有返回值。

参见

• ArrayIterator::offsetGet() Get value for an offset
• ArrayIterator::offsetSet() Set value for an offset

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

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);
?>

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.