如何使用索引表示法访问对象

时间:2015-10-01 14:51:49

标签: javascript json jsonlite

我正在尝试使用表格数据制作一个对象

 var cond = [
        { 
    "locality": "Dwarka",
    "Created ->OFP": "4.73",
    "OFP -> Picked": "2.16",
    "Picked - > Delivery": "14.91",
    "Over_All_TAT": "22.65",
    "Total_Order": "159" 
  },
  {
    "locality": "IIT & AIIMS",
    "Created ->OFP": "2.56",
    "OFP -> Picked": "9.74",
    "Picked - > Delivery": "19.41",
    "Over_All_TAT": "32.61",
    "Total_Order": "54"
  },
  {
    "locality": "Gk1 & Nehru Place",
    "Created ->OFP": "2.39",
    "OFP -> Picked": "6.87",
    "Picked - > Delivery": "14.06",
    "Over_All_TAT": "24.13",
    "Total_Order": "31"
  },
  {
    "locality": "Mayur Vihar",
    "Created ->OFP": "3.52",
    "OFP -> Picked": "1.24",
    "Picked - > Delivery": "15.3",
    "Over_All_TAT": "21.03",
    "Total_Order": "33"
  },
  {
    "locality": "Snapdeal_Mundhka",
    "Created ->OFP": "17.32",
    "OFP -> Picked": "4.65",
    "Picked - > Delivery": "100.32",
    "Over_All_TAT": "123.16",
    "Total_Order": "31"
  }
  ]

我知道密钥名称不符合规则,但这些是列名。我可以访问第二列说创建 - > OFP 使用索引(例如cond[0][1])。

我只能访问cond[i]如何访问内部块元素。

当我使用R时,json对象是使用jsonlite包创建的,所以,我有局限性。

3 个答案:

答案 0 :(得分:2)

您可以像这样访问内部块:

cond[i]['Created ->OFP']

循环示例:



var cond = [{
  "locality": "Dwarka",
  "Created ->OFP": "4.73",
  "OFP -> Picked": "2.16",
  "Picked - > Delivery": "14.91",
  "Over_All_TAT": "22.65",
  "Total_Order": "159"
}, {
  "locality": "IIT & AIIMS",
  "Created ->OFP": "2.56",
  "OFP -> Picked": "9.74",
  "Picked - > Delivery": "19.41",
  "Over_All_TAT": "32.61",
  "Total_Order": "54"
}, {
  "locality": "Gk1 & Nehru Place",
  "Created ->OFP": "2.39",
  "OFP -> Picked": "6.87",
  "Picked - > Delivery": "14.06",
  "Over_All_TAT": "24.13",
  "Total_Order": "31"
}, {
  "locality": "Mayur Vihar",
  "Created ->OFP": "3.52",
  "OFP -> Picked": "1.24",
  "Picked - > Delivery": "15.3",
  "Over_All_TAT": "21.03",
  "Total_Order": "33"
}, {
  "locality": "Snapdeal_Mundhka",
  "Created ->OFP": "17.32",
  "OFP -> Picked": "4.65",
  "Picked - > Delivery": "100.32",
  "Over_All_TAT": "123.16",
  "Total_Order": "31"
}]
var val;
cond.forEach(function(el) {
  val = el['Created ->OFP'];
  console.log(val);
});




答案 1 :(得分:1)

据我了解,您希望能够做的是:

cond[0][1];   // "4.73"

你不能这样做,因为cond[0]是和对象,并且不保证对象中键的顺序。因为Created ->OFP是您输入的第二个键 并不意味着它实际上是对象中的第二个键。您可以查看Object.keys(cond[0])可能的密钥将以相同的顺序返回,但不能依赖此

你需要做的是将数组中的对象(不是其他人指出的JSON)转换为数组本身。所以你最终得到的结果是:

[
    [
        "Dwarka",
        "4.73",
        "2.16",
        "14.91",
        "22.65",
        "159"
    ],...
]

然后你可以这样做:

cond[0][1];   //and get the first row and second column.

要将原始数据转换为数组数组,您可以执行以下操作:

// Note: this is the order **you** want the columns to be iterated in
var columns = ["locality",
    "Created ->OFP",
    "OFP -> Picked",
    "Picked - > Delivery",
    "Over_All_TAT",
    "Total_Order"];

var arrayOfArrays = cond.map(function (i) {
    return columns.map(function (prop) {
        return i[prop];
    });
});

console.log(arrayOfArrays[0][1]);   // logs 4.73

Fiddle

答案 2 :(得分:0)

您可以像这样访问您的元素:

cond[i]["Created ->OFP"]; // "4.73"

如果你想使用像1,2这样的索引,你有两个选择: 使用数组而不是对象,它将如下所示:

 var cond = [
        ["Dwarka", "4.73", "2.16", "14.91", "22.65", "159" ],
        [ ... ]
  }

或者您可以在对象上使用索引1,2 ...,如下所示:

var cond = [
        { 
    "0": "Dwarka",
    "1": "4.73",
    "2": "2.16",
    "3": "14.91",
    "4": "22.65",
    "5": "159" 
  },
  {...}
]

但除非您将其作为元素添加到对象中,否则您将无法找到属性length

我认为最适合您的解决方案是保持您的对象不变,并使用循环for(key in cond)

for(var i=0; i<cond.length; i++) {
    for(var key in cond[i]) {
       console.log(cond[i][key]);
    }
}