EasyPost\Shipment::lowest_rate PHP Method

    public function lowest_rate($carriers = array(), $services = array())
    {
        $lowest_rate = false;
        $carriers_include = array();
        $carriers_exclude = array();
        $services_include = array();
        $services_exclude = array();
        if (!is_array($carriers)) {
            $carriers = explode(',', $carriers);
        }
        for ($a = 0, $b = count($carriers); $a < $b; $a++) {
            $carriers[$a] = trim(strtolower($carriers[$a]));
            if (substr($carriers[$a], 0, 1) == '!') {
                $carriers_exclude[] = substr($carriers[$a], 1);
            } else {
                $carriers_include[] = $carriers[$a];
            }
        }
        if (!is_array($services)) {
            $services = explode(',', $services);
        }
        for ($c = 0, $d = count($services); $c < $d; $c++) {
            $services[$c] = trim(strtolower($services[$c]));
            if (substr($services[$c], 0, 1) == '!') {
                $services_exclude[] = substr($services[$c], 1);
            } else {
                $services_include[] = $services[$c];
            }
        }
        for ($i = 0, $k = count($this->rates); $i < $k; $i++) {
            $rate_carrier = strtolower($this->rates[$i]->carrier);
            if (!empty($carriers_include[0]) && !in_array($rate_carrier, $carriers_include)) {
                continue;
            }
            if (!empty($carriers_exclude[0]) && in_array($rate_carrier, $carriers_exclude)) {
                continue;
            }
            $rate_service = strtolower($this->rates[$i]->service);
            if (!empty($services_include[0]) && !in_array($rate_service, $services_include)) {
                continue;
            }
            if (!empty($services_exclude[0]) && in_array($rate_service, $services_exclude)) {
                continue;
            }
            if (!$lowest_rate || floatval($this->rates[$i]->rate) < floatval($lowest_rate->rate)) {
                $lowest_rate = clone $this->rates[$i];
            }
        }
        if ($lowest_rate == false) {
            throw new Error('No rates found.');
        }
        return $lowest_rate;
    }