Question

Stumped by this one:

I have a function that returns an array of folders in a given directory. When I iterate through the array, I can see all the items. However, if I try to print the first item, I get nothing:

function get_folders($dir) {
    return array_filter(scandir($dir), function ($item) use ($dir) {
        return (is_dir($dir.'/'.$item) && $item != "." && $item != "..") ;
    });
}
$folders = get_folders(".");
$first_folder = $folders[0]; 
echo $first_folder; // returns blank.

Interestingly, if I don’t filter out the “.” and “..”, then $first_folder does print “.”. Can anyone explain this?

Answer 1

From the array_filter manual:

Iterates over each value in the input array passing them to the callback function. If the callback function returns true, the current value from input is returned into the result array. Array keys are preserved.

So, scandir($dir) gets you an array with . at key 0, thus if you later filter . out, there will be nothing at key 0 in the result.

If you want to know what the first key of the resulting array is, try the array_keys function.

EDIT: actually, salathe’s suggestion to use array_values is better in your case than getting the keys from array_keys.