用于 OpenWeatherMap API 的 JSON

Question

我正在使用Openweathermap API 编写一个简单的单页天气应用程序，但在循环返回的嵌套 JSON 对象时遇到问题。

这是 JSON 的示例：

"cod":"200",
"message":0.1986,
"city":{
    "id":"4781530",
    "name":"Reston",
    "coord":{
        "lon":-77.3545,
        "lat":38.9597
    },
    "country":"United States of America",
    "population":0
},
"cnt":2,
"list":[
    {
        "dt":1416499200,
        "temp":{
            "day":45.3,
            "min":33.48,
            "max":52,
            "night":34.47,
            "eve":50.59,
            "morn":33.48
        },
        "pressure":1015.56,
        "humidity":58,
        "weather":[
            {
                "id":801,
                "main":"Clouds",
                "description":"few clouds",
                "icon":"02d"
            }
        ],
        "speed":9.07,
        "deg":212,
        "clouds":24
    },
    {
        "dt":1416585600,
        "temp":{
            "day":33.04,
            "min":20.55,
            "max":38.86,
            "night":22.87,
            "eve":38.03,
            "morn":24.42
        },
        "pressure":1027.28,
        "humidity":50,
        "weather":[
            {
                "id":800,
                "main":"Clear",
                "description":"sky is clear",
                "icon":"01d"
            }
        ],
        "speed":7.99,
        "deg":301,
        "clouds":0
    }
]

}

我能够成功循环遍历 obj.list 中的第一组值，但是当它到达 $.each(obj.list[i].weather[i], function(key,value) 循环时出现未定义的错误。

我将如何遍历嵌套的天气和临时对象，为什么我当前的代码会给我一个未定义的错误？我已经包含了代码和 Firebug 控制台日志。非常感谢任何帮助。

jQuery 循环函数

$.each(obj.list, function(i) {
    $.each(obj.list[i], function(key,value) {

        if(typeof value == "object"){
            console.log(key + " is an Object!!");

            if(key=="weather"){
                            console.log("What is i? " + i );
                            console.log(obj.list[i].weather[i]);

                            $.each(obj.list[i].weather[i], function(key,value) {
                                    console.log("weather object " + key + ": " + value );
                            });
            }

        }
        else{
            console.log("outer object " + key + ": " + value );
        }
    });
});

Firebug 控制台日志：

outer object dt: 1416499200
scripts.js (line 72)
temp is an Object!!
scripts.js (line 49)
outer object pressure: 1015.56
scripts.js (line 72)
outer object humidity: 58
scripts.js (line 72)
weather is an Object!!
scripts.js (line 49)
What is i? 0
scripts.js (line 59)
Object { id=801, main="Clouds", description="few clouds", more...}
scripts.js (line 60)
weather object id: 801
scripts.js (line 66)
weather object main: Clouds
scripts.js (line 66)
weather object description: few clouds
scripts.js (line 66)
weather object icon: 02d
scripts.js (line 66)
outer object speed: 9.07
scripts.js (line 72)
outer object deg: 212
scripts.js (line 72)
outer object clouds: 24
scripts.js (line 72)
***********
scripts.js (line 103)
outer object dt: 1416585600
scripts.js (line 72)
temp is an Object!!
scripts.js (line 49)
outer object pressure: 1027.28
scripts.js (line 72)
outer object humidity: 50
scripts.js (line 72)
weather is an Object!!
scripts.js (line 49)
What is i? 1
scripts.js (line 59)
undefined

Answer 1

您只要求每个 obj.list[i].weather 列表中的 ith 元素。您应该循环遍历obj.list[i].weather，而不是从中请求单个元素。因此，对于obj.list[0]，您只需要obj.list[0].weather[0]。对于obj.list[1]，您只要求obj.list[1].weather[1]，它不存在（weather 列表只有一个对象，位于索引0）。

您的$.each(obj.list[i].weather[i], ...) 循环遍历obj.list[i].weather[i]，但您不会循环遍历obj.list[i].weather。你需要两个不同的循环变量，比如obj.list[i].weather[j]，而不是obj.list[i].weather[i]。

    if(typeof value == "object"){
        console.log(key + " is an Object!!");

        if(key=="weather"){
                console.log("What is i? " + i );

                $.each(obj.list[i].weather, function(j) {
                    console.log(obj.list[i].weather[j]);
                    $.each(obj.list[i].weather[j], function(key,value) {
                        console.log("weather object " + key + ": " + value );
                    });
                });
        }

    }

在这里，我们使用内部循环变量j 在obj.list[i].weather 上添加一个循环，以便我们获得每个weather 列表中的所有项目，而不是只有一个..