public function getSigFigs($n)
{
$n = ltrim($n, '0+-');
$dp = strpos($n, '.');
// decimal position
if ($dp === false) {
$sigfigs = strlen(rtrim($n, '0'));
} else {
$sigfigs = strlen(ltrim($n, '0.'));
// eliminate extra decimal character
if ($dp !== 0) {
$sigfigs--;
}
}
return $sigfigs;
}