从 JavaScript 对象中提取数据

Question

如何将下面对象中的“汇率”值“18.52005000”分配给 JavaScript 变量？

{
    "Realtime Currency Exchange Rate": {
        "1. From_Currency_Code": "USD",
        "2. From_Currency_Name": "United States Dollar",
        "3. To_Currency Code": "MXN",
        "4. To_Currency_Name": "Mexican Peso",
        "5. Exchange Rate": "18.52005000",
        "6. Last Refreshed": "2018-02-17 12:53:11",
        "7. Time Zone": "UTC"
    }
}

我了解一点 JavaScript - 我为货币兑换率 API 编写的一个脚本，我只需要汇率部分来完成其余的计算。

我正在做这样的事情来创建对象：

var http_response = httpGet(query_url);
var http_response_json = JSON.parse(http_response);

谢谢！

Answer 1

如果您的 Json 结构位于变量“

test

”中，则执行

test["Realtime Currency Exchange Rate"]["5. Exchange Rate"]

来访问其值

"18.52005000"

Answer 2

就像这样我的好先生：

var rate = http_response_json['Realtime Currency Exchange Rate']['5. Exchange Rate']

Answer 3

您可以通过两种方式访问对象属性：

1. object.prop

2. object['prop']

如果属性名称有问题或可变，则需要选择 2。

var data = {
    "Realtime Currency Exchange Rate": {
        "1. From_Currency_Code": "USD",
        "2. From_Currency_Name": "United States Dollar",
        "3. To_Currency Code": "MXN",
        "4. To_Currency_Name": "Mexican Peso",
        "5. Exchange Rate": "18.52005000",
        "6. Last Refreshed": "2018-02-17 12:53:11",
        "7. Time Zone": "UTC"
    }
}

var rate = data["Realtime Currency Exchange Rate"]["5. Exchange Rate"]

console.log(rate)

Answer 4

一旦获得

http_response_json

中的 JSON 对象，您就可以执行类似的操作来获取

Exchange Rate

的值

var http_response_json = {
    "Realtime Currency Exchange Rate": {
        "1. From_Currency_Code": "USD",
        "2. From_Currency_Name": "United States Dollar",
        "3. To_Currency Code": "MXN",
        "4. To_Currency_Name": "Mexican Peso",
        "5. Exchange Rate": "18.52005000",
        "6. Last Refreshed": "2018-02-17 12:53:11",
        "7. Time Zone": "UTC"
    }
};
var value = http_response_json["Realtime Currency Exchange Rate"]["5. Exchange Rate"];
console.log(value);

Answer 5

var exchangeRate =  http_response_json["Realtime Currency Exchange Rate"]["5. Exchange Rate"];