src/Zicht/Bundle/FrameworkExtraBundle/Twig/Extension.php
public function strUscore($str, $camelFirst = true)
    {
        if ($camelFirst) {
            $str = StrUtil::camel($str);
        }
        return StrUtil::uscore($str);
    }
public function strUscore($str, $camelFirst = true)
    {
        if ($camelFirst) {
            $str = StrUtil::camel($str);
        }
        return StrUtil::uscore($str);
    }
public function strUscore ( $ str , $ camelFirst = true ) { if ( $ camelFirst ) { $ str = StrUtil :: camel ( $ str ) ; } return StrUtil :: uscore ( $ str ) ; }
CamelCased to under_score

@param string $str
@param bool $camelFirst
@return string
CamelCased to under_score