PHP：Array从数组变量中删除特定键

I have an array, the array key contains the file name and array value will be another array which contain sfile size,date etc.

In these array list, I want to store only xls and xlsx files alone. I need to remove files of all other extensions.

Is there any predefined function in PHP?

Note: i have constant variable this varaible contain the like VAR_FILE_EXT= "xls, xlsx, csv"

[sample.xls] => Array (
            [size] => 3353
            [uid] => 1012
            [gid] => 1013
            [permissions] => 33188
            [atime] => 1338497357
            [mtime] => 1338497357
            [type] => 1
        )

[sample.csv] => Array (
            [size] => 3353
            [uid] => 1012
            [gid] => 1013
            [permissions] => 33188
            [atime] => 1338497357
            [mtime] => 1338497357
            [type] => 1
        )

[sample.txt] => Array (
            [size] => 3353
            [uid] => 1012
            [gid] => 1013
            [permissions] => 33188
            [atime] => 1338497357
            [mtime] => 1338497357
            [type] => 1
        )

in this example i want remove only sample.txt array keys and its corresponding values.

$filtered = array_intersect_key(
    $array,
    array_filter(array_keys($array), function ($name) { return preg_match('/\.xlsx?$/', $name); })
);

$your_array = array(
    'sample.xls' => ...
    'sample.csv' => ...
    'sample.txt' => ...
);

$extensions = '/('.str_replace(', ', '|', $VAR_FILE_EXT).')$/i';
$new_array = array();

foreach ($your_array as $file => $stuff) {
    if (preg_match($extensions, $file)) {
        $new_array[$file] => $stuff;
    }
}

Then you use $new_array.