$_FILES super global variable

Solution for $_FILES super global variable
is Given Below:

why doesn’t the unset function remove $_FILES contents or empty it after uploading a file .
how can I empty my $FILES variable after uploading a file .

<html>
    <head>
            <title>Files Upload</title>
    </head>
    <body>
            <form action="" method="post" enctype="multipart/form-data">
                <input type="file" name="pdf" id="pdf"><br>
                <input type="submit" name="sumbit" value="upload">
            </form>
    </body>
</html>
<?php
unset($GLOBALS['$_FILES']);
echo "<pre>";
var_dump($_FILES);
echo "</pre>";
?>

The Output is :
array(1) {
  ["pdf"]=>
  array(5) {
    ["name"]=>
    string(19) "Courses Degrees.pdf"
    ["type"]=>
    string(15) "application/pdf"
    ["tmp_name"]=>
    string(24) "C:xampptmpphp6BBD.tmp"
    ["error"]=>
    int(0)
    ["size"]=>
    int(624129)
  }
}

You have to specify the key of the variable

unset($_FILES['key']);

Your key is probably “pdf” when looking at your output

unset($_FILES['pdf']);