Question

我正在尝试根据用户插入的邮政编码自动填充城市和州值。我无法将输入的邮政编码与json对象中提供的zip进行比较。 obj长度的值为1，必须为3.

var text = '{"zipcodes":[' +
'{"zip":"22031","city":"Fairfax" ,"State":"VA" },' +
'{"zip":"22032","city":"AshBurn" ,"State":"VA" },' +
'{"zip":"22033","city":"Tysons" ,"State":"VA" }]}';

var obj = JSON.parse(text);
var n = Object.keys(obj).length;

for(i=0; i<=n; i++){

    if(obj.zipcodes[i].zip.parseInt() == zipcodes.parseInt()){

        document.getElementById("city").value = obj.zipcodes[i].city;
        document.getElementById("state").value = obj.zipcodes[i].State;

    }
}

Answer 1

解析后的对象变为：

{
  "zipcodes":[
    {"zip":"22031","city":"Fairfax" ,"State":"VA" },
    {"zip":"22032","city":"AshBurn" ,"State":"VA" },
    {"zip":"22033","city":"Tysons" ,"State":"VA" }]}
  ]
};

因此对象的密钥数是1，即zipcodes。如果你想要数量的邮政编码，

使用此：

var obj = JSON.parse(text);
var n = obj.zipcodes.length;

Answer 2

Haven没有试过这段代码，但看起来你真的只得到了一个关键字，这就是＆＃39; zipcodes＆＃39;。

我认为你应该通过obj [＆＃39; zipcodes＆＃39;]来代替？

Answer 3

是的，确实长度为1。如果您想迭代邮政编码，那么对于上面给出的代码片段，我会这样做：

var n = obj.zipcodes.length;
//continue your computation here.

obj的长度是1 - javascript

3 个答案: