Move empty value to the end of the array

I have an array something like below.

Array
(
    [0] => 100
    [1] => 
    [2] => 107
    [3] => 109
)

I may get empty value more than one also. I just wanted to move the empty values to down.

I'd just sort it in reverse order

arsort($myarray, SORT_NUMERIC);

You'd end up with the values:

109, 107, 100, <blank>

Edit: to get the values in the order specified in the below comment:

// initial data
$a = (100, '', 107, 109);

// define functions to detect blank/notblank
function isBlank($var) {
    return $var == '';
}

function isNotBlank($var) {
    return !isBlank($var);
}

// get two arrays, one containing blanks, one containing numbers
$blanks = array_filter($a, 'isBlank');
$notBlanks = array_filter($a, 'isNotBlank');

// reverse sort the numbers
arsort($notBlanks, SORT_NUMERIC);

// merge the arrays
$output = array_merge($notBlanks, $blanks);

array_merge documentation