Question

我有一个json文件，其结构如下：

{
    "gasStationID":"441",
    "gasStationLat":"39.6337420",
    "gasStationLong":"22.4324412",
    "fuelCompID":"6",
    "fuelCompNormalName":"AVIN",
    "ddID":"42010100",
    "municipalityID":"42010000",
    "countyID":"42000000",
    "phone1":null,
    "username":"user1",
    "fuelTypeID":"1",
    "fuelPrice":"1.379"
},
{
    "gasStationID":"441",
    "gasStationLat":"39.6337420",
    "gasStationLong":"22.4324412",
    "fuelCompID":"6",
    "fuelCompNormalName":"AVIN",
    "ddID":"42010100",
    "municipalityID":"42010000",
    "countyID":"42000000",
    "phone1":null,
    "username":"user1",
    "fuelTypeID":"1",
    "fuelPrice":"1.478"
}

所以，我的问题是如何使用fuelPrice检索fuelTypeID=1？

我的JavaScript文件是：

for (i = 0; i < obj.length; i++) {
    var _gasStationCompName = obj[i].fuelCompNormalName;
    var priceID = obj[i].fuelTypeID;
    switch (fuelId) {
        case '1':
        case priceID == 1:
            price = obj[i].fuelPrice;
            break;
        case '2':
        case priceID == 2:
            price = obj[i].fuelPrice;
            break;
        default:
            price = "0";
    }

我的问题是price = obj[i].fuelPrice只显示fuelPrice fuelType=2。如何在switch语句中过滤结果？

在此之前，我正在解析JSON文件。此外，您可以看到我有case: '1'。那是因为我的HTML文件中有这样的东西：

<div>
        <select onChange="getData(this.value);">
            <option value="1">Gas</option>
            <option value="2">Diesel</option>
        </select>
</div>

Answer 1

变量和对象键区分大小写（A！= a）;

for (i = 0; i < obj.length; i++) {
  var _gasStationCompName = obj[i].fuelCompNormalName;
  var priceID = obj[i].fuelTypeID; // fuelTypeId => fuelTypeID
  switch (priceID) { fuelTypeId // => priceID 
      case '1':
      case priceID == 1:
          price = obj[i].fuelPrice;
          break;
      case '2':
      case priceID == 2:
          price = obj[i].fuelPrice;
          break;
      default:
          price = "0";
  }
}

Answer 2

我假设JSON是一个数组。让我们调用该数组gasStations。

// Given a collection of stations and a fuel type, find the price

function findPrice(collection, fuelType) {
  // Find the station with the target fuel type
  var targetStation = collection.filter(function (station) {
    return station.fuelTypeID === fuelType;
  })[0];

  // If there was a match, return that station's price
  if (targetStation) {
    return targetStation.fuelPrice;
  }

  // Default to "0" if there was no match
  return "0";
}

// usage
var price = findPrice(gasStations, "1");

注意：如果您有一个集合，其中多个工作站具有目标燃料类型，此功能将返回具有该燃料类型的第一个加油站的价格。

Answer 3

我设法找到了解决方案。这是一个正确的开关语句，就像一个魅力：

                       var priceID = obj[i].fuelTypeID;
                        switch (fuelTypeID) {
                            case '1':
                                if (priceID == 1) {
                                    price = obj[i].fuelPrice;
                                }
                                break;
                            case '2':
                                if (priceID == 2) {
                                    price = obj[i].fuelPrice;
                                }
                                break;
                            default:
                                price = 0;
                        }

使用where语句从JSON检索数据

3 个答案: