javascript - 使用 javascript 或 jquery 计算对象中 JSON 对象的数量

Question

我有来自 AJAX 响应的 JSON 数据，如下所示

    {
        "2015001":{"sname":"name1","01-07-2015":null,"02-07-2015":"0","03-07-2015":"0","04-07-2015":"0","05-07-2015":null,"06-07-2015":"0","07-07-2015":"0","08-07-2015":"0","09-07-2015":"0","10-07-2015":"0","11-07-2015":null,"12-07-2015":null,"13-07-2015":"0","14-07-2015":"1","15-07-2015":null,"16-07-2015":"2","17-07-2015":null,"18-07-2015":null,"19-07-2015":null,"20-07-2015":"2","21-07-2015":"0","22-07-2015":"0","23-07-2015":"0","24-07-2015":"1","25-07-2015":"1","26-07-2015":null,"27-07-2015":"2","28-07-2015":null,"29-07-2015":"2","30-07-2015":"2","31-07-2015":"2"},
        "2015002":{"sname":"name2","01-07-2015":null,"02-07-2015":"0","03-07-2015":"1","04-07-2015":"1","05-07-2015":null,"06-07-2015":"0","07-07-2015":"0","08-07-2015":"0","09-07-2015":"0","10-07-2015":"2","11-07-2015":null,"12-07-2015":null,"13-07-2015":"1","14-07-2015":"1","15-07-2015":null,"16-07-2015":"2","17-07-2015":null,"18-07-2015":null,"19-07-2015":null,"20-07-2015":"0","21-07-2015":"0","22-07-2015":"0","23-07-2015":"0","24-07-2015":"0","25-07-2015":"0","26-07-2015":null,"27-07-2015":"0","28-07-2015":null,"29-07-2015":"0","30-07-2015":"0","31-07-2015":"0"},
        "2015003":{"sname":"name3","01-07-2015":null,"02-07-2015":"2","03-07-2015":"2","04-07-2015":"2","05-07-2015":null,"06-07-2015":"2","07-07-2015":"2","08-07-2015":"0","09-07-2015":"2","10-07-2015":"2","11-07-2015":null,"12-07-2015":null,"13-07-2015":"2","14-07-2015":"0","15-07-2015":null,"16-07-2015":"2","17-07-2015":null,"18-07-2015":null,"19-07-2015":null,"20-07-2015":"2","21-07-2015":"2","22-07-2015":"0","23-07-2015":"2","24-07-2015":"2","25-07-2015":"2","26-07-2015":null,"27-07-2015":"2","28-07-2015":null,"29-07-2015":"2","30-07-2015":"2","31-07-2015":"2"},
        "2015004":{"sname":"name4","01-07-2015":null,"02-07-2015":"2","03-07-2015":"2","04-07-2015":"2","05-07-2015":null,"06-07-2015":"0","07-07-2015":"2","08-07-2015":"2","09-07-2015":"2","10-07-2015":"2","11-07-2015":null,"12-07-2015":null,"13-07-2015":"2","14-07-2015":"2","15-07-2015":null,"16-07-2015":"2","17-07-2015":null,"18-07-2015":null,"19-07-2015":null,"20-07-2015":"0","21-07-2015":"2","22-07-2015":"2","23-07-2015":"2","24-07-2015":"2","25-07-2015":"0","26-07-2015":null,"27-07-2015":"2","28-07-2015":null,"29-07-2015":"0","30-07-2015":"2","31-07-2015":"2"},
        "2015005":{"sname":"name5","01-07-2015":null,"02-07-2015":"2","03-07-2015":"2","04-07-2015":"0","05-07-2015":null,"06-07-2015":"2","07-07-2015":"2","08-07-2015":"2","09-07-2015":"2","10-07-2015":"2","11-07-2015":null,"12-07-2015":null,"13-07-2015":"2","14-07-2015":"2","15-07-2015":null,"16-07-2015":"2","17-07-2015":null,"18-07-2015":null,"19-07-2015":null,"20-07-2015":"0","21-07-2015":"2","22-07-2015":"2","23-07-2015":"2","24-07-2015":"2","25-07-2015":"2","26-07-2015":null,"27-07-2015":"2","28-07-2015":null,"29-07-2015":"2","30-07-2015":"2","31-07-2015":"2"},
        "2015006":{"sname":"name6","01-07-2015":null,"02-07-2015":"2","03-07-2015":"2","04-07-2015":"2","05-07-2015":null,"06-07-2015":"2","07-07-2015":"2","08-07-2015":"2","09-07-2015":"2","10-07-2015":"2","11-07-2015":null,"12-07-2015":null,"13-07-2015":"2","14-07-2015":"2","15-07-2015":null,"16-07-2015":"2","17-07-2015":null,"18-07-2015":null,"19-07-2015":null,"20-07-2015":"2","21-07-2015":"0","22-07-2015":"2","23-07-2015":"2","24-07-2015":"2","25-07-2015":"2","26-07-2015":null,"27-07-2015":"2","28-07-2015":null,"29-07-2015":"2","30-07-2015":"2","31-07-2015":"2"}
    }

每个对象都有相同数量的对象。这里我想计算第一个对象(2015001)中的对象数量。 key 将根据每次请求而更改。

我试过了

console.log(Object.keys(data[2015001]).length)

我得到了我需要的

但是没有 key 我该怎么办(2015001)

Answer 1

如果你总是想知道第一个对象的键的数量，那么你应该使用Object.keys(data[Object.keys(data)[0]]).length

请注意，如果顺序对您很重要，您应该将键发送到数组内而不是对象内，因为根据规范，对象是一组无序的名称/值对。