How can I strip whitespace only elements from an array?

Question

How I can remove all elements of an array that contain just whitespace, not whitespace in an element like \"foobar \" but just empty array elements like <

Answer 1

$arr = array("This", " ", "is", " ", "a", " ", "test.");
$result = array();
for($arr as $x) {
     if(!preg_match("/^\s*$/", $x)) $result[] = $x;
}
$arr = $result;