PHP AppendIterator key () Function

PHP

Syntax:
scalar AppendIterator::key (void)
Parameters:This function takes no parameters.Return Value:This function returns the current key, if valid, or NULL otherwise. The following programs illustrate the AppendIterator::key() function in PHP:Program 1:  
// Declare ArrayIterator $arr1 = new ArrayIterator ( array ( 'G' , 'e' , 'e' , ' k' , ' s' ));  
// Create a new AppendIterator $itr = new AppendIterator;  
// Add an ArrayIterator element $itr -> append ( $arr1 );  
// Show result while ( $itr -> valid()) { echo " ArrayIterator Key: " . $itr -> key(). " ArrayIterator Value:" . $itr -> current(). "" ; $itr -> next(); }  
?>
Exit:
ArrayIterator Key: 0 ArrayIterator Value: G ArrayIterator Key: 1 ArrayIterator Value: e ArrayIterator Key: 2 ArrayIterator Value: e ArrayIterator Key: 3 ArrayIterator Value: k ArrayIterator Key: 4 ArrayIterator Value: s
Program 2:  
// Declare ArrayIterator $arr1 = new ArrayIterator ( array ( "a" = > "Geeks" , " b " = > "for" , "c" = > "Geeks" )); $arr2 = new ArrayIterator ( array ( "x" = > "Computer" , "y" = > " Science " , " z " = > " Portal " ) );  
// Create a new AppendIterator $itr = new AppendIterator; $itr -> append ( $arr1 ); $itr -> append ( $arr2 ); $itr -> rewind ();  
// Show result while ( $itr -> valid()) { echo " ArrayIterator Key: " . $itr -> key(). " ArrayIterator Value:" . $itr -> current(). "" ; $itr -> next(); }  
?>
Exit:
ArrayIterator Key: a ArrayIterator Value: Geeks ArrayIterator Key: b ArrayIterator Value: for ArrayIterator Key: c ArrayIterator Value: Geeks ArrayIterator Key: x ArrayIterator Value: Computer ArrayIterator Key: y ArrayIterator Value: Science ArrayIterator Key: z ArrayIterator Value: Portal  Link: https://www.php.net/manual/en/appenditerator .key.php