Question

任何人都可以帮助我使用以下功能，为什么return内部切换工作正常（返回正确的转换价格/数量）：

function calcPriceAndQuantityFromLBS($price, $quantity, $unit_id, $lbs_in_a_bu, $lbs_in_w_bu) {
    switch ($unit_id) {
        case 8: // A Bushel
            $outQ = $quantity / $lbs_in_a_bu;
            $outP = $price * $lbs_in_a_bu;
            return ['quantity' => number_format($outQ, 3, '.', ''), 'price' => number_format($outP, 8, '.', '')];
        case 10: // Pounds
            $outQ = $quantity;
            $outP = $price;
            return ['quantity' => number_format($outQ, 3, '.', ''), 'price' => number_format($outP, 8, '.', '')];
        case 11: // CWT
            $outQ = $quantity / LBS_IN_CWT;
            $outP = $price * LBS_IN_CWT;
            return ['quantity' => number_format($outQ, 3, '.', ''), 'price' => number_format($outP, 8, '.', '')];
        case 12: // Metric Tonne
            $outQ = $quantity / LBS_IN_TON;
            $outP = $price * LBS_IN_TON;
            return ['quantity' => number_format($outQ, 3, '.', ''), 'price' => number_format($outP, 8, '.', '')];
        case 136: // W Bushel
            $outQ = $quantity / $lbs_in_w_bu;
            $outP = $price * $lbs_in_w_bu;
            return ['quantity' => number_format($outQ, 3, '.', ''), 'price' => number_format($outP, 8, '.', '')];
    }
}

但这个不是吗？（仅返回case 136转换后的价格/数量）（切换后无效return）如何从上面的改进，我想用更少的代码来完成上述功能，谢谢！

function calcPriceAndQuantityFromLBS($price, $quantity, $unit_id, $lbs_in_a_bu, $lbs_in_w_bu) {
    switch ($unit_id) {
        case 8: // A Bushel
            $outQ = $quantity / $lbs_in_a_bu;
            $outP = $price * $lbs_in_a_bu;
        case 10: // Pounds
            $outQ = $quantity;
            $outP = $price;
        case 11: // CWT
            $outQ = $quantity / LBS_IN_CWT;
            $outP = $price * LBS_IN_CWT;
        case 12: // Metric Tonne
            $outQ = $quantity / LBS_IN_TON;
            $outP = $price * LBS_IN_TON;
        case 136: // W Bushel
            $outQ = $quantity / $lbs_in_w_bu;
            $outP = $price * $lbs_in_w_bu;
    }
    return ['quantity' => number_format($outQ, 3, '.', ''), 'price' => number_format($outP, 8, '.', '')];
}

Answer 1

在每个break;的末尾添加case语句。否则，case语句的下一个switch的代码也将被执行。您的return语句使用switch语句中定义的变量。如果某个$unit_id不在case列表中，则return将失败。为防止return失败，您可以在案例列表的底部添加：

default:  // $unit_id not found
  return ['quantity' => '0.000', 'price' => '0.000'];  // whatever you like

或者你可以抛出异常。

Answer 2

返回退出函数，所以在你的情况下作为一个休息，这就是它在第一种情况下工作的原因。

php返回内部交换机案例正在工作但在交换机不工作后返回

2 个答案: