PHP | ArrayIterator ksort() Function

The ArrayIterator::ksort() function is an inbuilt function in PHP which is used to sort the array element by key.

Syntax:

void ArrayIterator::ksort( void )

Parameters: This function does not accept any parameters.

Return Value: This function does not return any value.

Below programs illustrate the ArrayIterator::ksort() function in PHP:

Program 1:

<?php

// Declare an ArrayIterator
$arrItr = new ArrayIterator(
    array(
        5 => 'G',
        4 => 'e',
        3 => 'e',
        2 => 'k',
        1 => 's',
        6 => 'f',
        8 => 'o',
        7 => 'r'
    )
);

// Sort the array element by key
$arrItr->ksort();

// Display the element
while($arrItr->valid()) {
    echo $arrItr->current() . " ";
    $arrItr->next();
}

?>

Output:

s k e e G f r o

Program 2:

<?php

// Declare an ArrayIterator
$arrItr = new ArrayIterator(
    array(
        "a" => "Geeks",
        "c" => "for",
        "b" => "Geeks"
    )
);

// Append the element into array
$arrItr->append("Computer");
$arrItr->append("Science");
$arrItr->append("Portal");

// Sort the array element by key
$arrItr->ksort();

// Display the result
foreach($arrItr as $element) {
    echo "key: " . $arrItr->key() . "  Value: "
            . $arrItr->current() . "\n";
}

?>

Output:

key: a  Value: Geeks
key: b  Value: Geeks
key: c  Value: for
key: 0  Value: Computer
key: 1  Value: Science
key: 2  Value: Portal

Reference: https://www.php.net/manual/en/arrayiterator.ksort.php