PHP | AppendIterator valid() Function

The AppendIterator::valid() function is an inbuilt function in PHP which is used to check the validity of the current element.

Syntax:

bool AppendIterator::valid( void )

Parameters: This function does not accept any parameters.

Return Value: This function returns TRUE if the current iteration is valid and FALSE otherwise.

Below programs illustrate the AppendIterator::valid() function in PHP:

Program 1:

<?php

// Declare an ArrayIterator
$arr = new ArrayIterator(array('G', 'e', 'e', 'k', 's'));

// Create a new AppendIterator
$itr = new AppendIterator;
$itr->append($arr);

// Check the validity and display
// the result
while($itr->valid()) {
    echo $itr->current();
    $itr->next();
}

?>

Output:

Geeks

Program 2:

<?php

// Declare an ArrayIterator
$arr1 = new ArrayIterator(array("Geeks", "for", "Geeks"));
$arr2 = new ArrayIterator(array("Computer", "Science", "Portal"));

// Create a new AppendIterator
$itr = new AppendIterator;
$itr->append($arr1);
$itr->append($arr2);

// Using rewind function
$itr->rewind();

// Check the validity and display the result
while($itr->valid()) {
    var_dump($itr->current());

    // Moving to next element
    $itr->next();
}

?>

Output:

string(5) "Geeks"
string(3) "for"
string(5) "Geeks"
string(8) "Computer"
string(7) "Science"
string(6) "Portal"

Reference: https://www.php.net/manual/en/appenditerator.valid.php