PHP | ArrayIterator offsetExists() Function

The ArrayIterator::offsetExists() function is an inbuilt function in PHP which is used to check the existence of offset at the given index.

Syntax:

bool ArrayIterator::offsetExists( mixed $index )

Parameters: This function accepts single parameter $index which holds the index value to check the existence of offset.

Return Value: This function returns TRUE if the offset exists, otherwise returns FALSE.

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

Program 1:

<?php

// Declare an ArrayIterator
$arrItr = new ArrayIterator(
    array(
        "a" => 4,
        "b" => 2,
        "g" => 8,
        "d" => 6,
        "e" => 1,
        "f" => 9
    )
);

// Display the offset value
var_dump($arrItr->offsetGet("a"));

// Check the existence of offset
var_dump($arrItr->offsetExists("a"));

// Unset the offset value
var_dump($arrItr->offsetUnset("a"));

// Check the existence of offset
var_dump($arrItr->offsetExists("a"));

?>

Output:

int(4)
bool(true)
NULL
bool(false)

Program 2:

<?php

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


// Print the value at index 1
echo $arrItr->offsetGet(1) . "\n";

// Check the existence of offset
var_dump($arrItr->offsetExists(1));

// Unset the offset value
var_dump($arrItr->offsetUnset(1));

// Check the existence of offset
var_dump($arrItr->offsetExists(1));

// Print the value at index 0
echo $arrItr->offsetGet(0) . "\n";

// Check the existence of offset
var_dump($arrItr->offsetExists(0));

// Unset the offset value
var_dump($arrItr->offsetUnset(0));

// Check the existence of offset
var_dump($arrItr->offsetExists(0));

?>

Output:

Geeks
bool(true)
NULL
bool(false)
for
bool(true)
NULL
bool(false)

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