PHP | FilesystemIterator key() Function

The FilesystemIterator::key() function is an inbuilt function in PHP which is used to retrieve the key for the current file.

Syntax:

string FilesystemIterator::key( void )

Parameters: This function does not accept any parameters.

Return Value: This function returns the pathname or filename depending on the set flags.

Below programs illustrate the FilesystemIterator::key() function in PHP:

Program 1:

<?php

// Create new file system iterator
$fileItr = new FilesystemIterator(dirname(__FILE__),
        FilesystemIterator::KEY_AS_FILENAME);

// Loop runs for each element of file iterator
foreach($fileItr as $it) {

    // Display the key
    echo $fileItr->key() . "<br>";
}

?>

Output:

applications.html
bitnami.css
dashboard
favicon.ico
gfg.php
img
index.php
webalizer
xampp

Program 2:

<?php

// Create new file system iterator
$fileItr = new FilesystemIterator(dirname(__FILE__),
        FilesystemIterator::KEY_AS_FILENAME);

// Loop runs while file iterator is valid
while ($fileItr->valid()) {

    // Check for non directory files
    if (!$fileItr->isDir()) {

        // Display the key
        echo $fileItr->key() . "<br>";
    }

    // Move to the next element
    $fileItr->next();
}

?>

Output:

applications.html
bitnami.css
favicon.ico
gfg.php
index.php

Note: The output of this function depends on the content of server folder.

Reference: https://www.php.net/manual/en/filesystemiterator.key.php