Flatten array example

flattenArray.php

<?php

$foo = [5,7,8,2,[6,1,3,4],523,0.52,'foo',new DateTime,[123,[52, [0], -50], [9]]];

/**
 * Returns a flat array of input integer values. Non-integer values filtered out.
 * 
 * @param  array  $input Arbitrarily nested array of integers.
 * @return array        
 */
function flattenArray(array $input) {
    $flattened = [];

    foreach ($input as $value) {
        if (is_integer($value)) {
            $flattened[] = $value;
        }
        elseif (is_array($value)) {
            $flattened = array_merge($flattened, flattenArray($value));
        }
    }

    return $flattened;
}

echo '<pre>';
print_r(flattenArray($foo));
exit();