Question

我在jQuery中有一个对象

obj[{timestamp:1499385600},{timestamp:1499385600},{timestamp:1499385600}, {timestamp:1499299200}, {timestamp:1499299200}, ...]

现在我需要一个对象，我将具有特定时间戳的所有计数作为名称，值对。例如。

{{timestamp: 1499385600, count: 3}, {timestamp: 1499299200, count:2}}

无法理解如何在此循环循环。到目前为止我已经完成了

var newobj={};
for(i=0;i<obj.length;i++){
   newobj['timestamp']=obj[i].timestamp;
   newobj['count']=//Not sure what to write here to get the count
}

建议表示赞赏。感谢

Answer 1

忽略问题中的所有语法错误并采取适当的假设，这可能是您想要做的：

var data = [
  {timestamp:1499385600},
  {timestamp:1499385600},
  {timestamp:1499385600}, 
  {timestamp:1499299200}, 
  {timestamp:1499299200}
];

var groups = data.reduce(function(acc, obj){
  acc[obj.timestamp] = acc[obj.timestamp] || 0;
  acc[obj.timestamp] += 1;
  return acc;
}, {});

var result = Object.keys(groups).map(function(key) {
  return {
    timestamp : key,
    count : groups[key]
  };
});

console.log(result);

首先创建一个地图，使用Array#reduce跟踪相同时间戳值的计数，然后在Object.keys()和Array#map

的帮助下创建最终数组

Answer 2

循环完成后，您希望newObj看起来像：

{
   '1499385600':6,
   '1499299200':2
}

然后你可以迭代newObj来创建你想要的新数组

// create counter object
var newobj = {};
for(var i = 0; i < obj.length; i++){
    // use current object timestamp as key
    // if undefined (first time found) make it zero +1 
    // otherwise add 1 to prior count                                
    newobj[obj[i].timestamp] = (newobj[obj[i].timestamp] || 0) +1;
}
// create results array from counter object
var results = [];
for(var time in newObj){
   results.push( { timestamp: time, count: newObj[time] });
}

想要在jQuery中实现具有相似值的数组的数组

2 个答案: