Things to note when traversing directories with is_file() and is_dir()

$dir = $_SERVER['DOCUMENT_ROOT'];
$dir = "$dir/inc/";
$d = opendir($dir);
while(false !==($f=readdir ($d)))
{
if(is_file($f)){
echo " $f ";
}else{
echo "  is the directory $f < ;/h2>";
}
}
closedir($d);

The result only shows that "footer.html" is a file, and the others have become directories: is a directory. It's a directory.. Is directory a footer.html Is the directory header.html Is the directory login_function.inc.php Is the directory mysqli_connect.php It’s the directory style.css

This is because "$f" cannot be used directly in is_file and is_dir. This will be regarded by PHP as the file in the root directory. However, there is the file footer.html in my root directory, so this will be displayed correctly. document. Others don't. Change the code to: To display correctly, the code needs to be modified:

while(false !== ($f=readdir($d)))
{
if(is_file("$dir/$f")){
echo "$f< /h2>";
}else{
echo " is the directory $f";
}
}
closedir($d);