AppendIterator::key

(PHP 5 >= 5.1.0)

AppendIterator::key — Gets the current key

说明

public scalar AppendIterator::key ( void )

Get the current key.

参数

此函数没有参数。

返回值

The current key if it is valid or NULL otherwise.

范例

Example #1 AppendIterator::key() basic example

  <?php
$array_a  = new  ArrayIterator (array( 'a'  =>  'aardwolf' ,  'b'  =>  'bear' ,  'c'  =>  'capybara' ));
 $array_b  = new  ArrayIterator (array( 'apple' ,  'orange' ,  'lemon' ));

 $iterator  = new  AppendIterator ;
 $iterator -> append ( $array_a );
 $iterator -> append ( $array_b );

 // Manual iteration
 $iterator -> rewind ();
while ( $iterator -> valid ()) {
    echo  $iterator -> key () .  ' '  .  $iterator -> current () .  PHP_EOL ;
     $iterator -> next ();
}

echo  PHP_EOL ;

 // With foreach
 foreach ( $iterator  as  $key  =>  $current ) {
    echo  $key  .  ' '  .  $current  .  PHP_EOL ;
}
 ?>

以上例程会输出：

a aardwolf
b bear
c capybara
0 apple
1 orange
2 lemona aardwolf
b bear
c capybara
0 apple
1 orange
2 lemon

参见

Iterator::key() - 返回当前元素的键
AppendIterator::current() - Gets the current value
AppendIterator::valid() - Checks validity of the current element
AppendIterator::next() - Moves to the next element
AppendIterator::rewind() - Rewinds the Iterator