按两个属性对对象数组进行排序

Question

我有一个我想要按两个属性排序的对象数组:

1. RemindingTimestamp
2. ModificationTimestamp

排序顺序:desc

通过一个属性对此对象进行排序不是问题,但在这种情况下,我不知道如何使其工作.

Answer 1

假设时间戳本身排序正常(例如ISO8601和相同的时区),请尝试:

myArray.sort(function(a,b) {
  var x = a.RemindingTimestamp - b.RemindingTimestamp;
  return x == 0? a.ModificationTimestamp - b.ModificationTimestamp : x;
}

编辑 - 对评论的回应

通过改变减法的顺序或将结果乘以-1来实现降序排序.由于没有减去而没有排序的日期(例如2012-04-12)可以通过首先转换为日期来处理,例如

// Convert ISO8601 date string to date object
// Assuming date is ISO8601 long format, ignores timezone
function toDate(s) {
  var bits = s.split(/[-T :]/);
  var d = new Date(bits[0], bits[1]-1, bits[2]);
  d.setHours(bits[3], bits[4], parseFloat(bits[5])); 
  return d;
}

// Source data, should end up sorted per n
var myArray = [ 
  {RemindingTimestamp: '2012-04-15T23:15:12Z', 
   ModificationTimestamp: '2012-04-15T23:15:12Z', n: 4},
  {RemindingTimestamp: '2012-04-12T23:15:12Z', 
   ModificationTimestamp: '2012-04-12T23:15:12Z', n: 1},
  {RemindingTimestamp: '2012-04-12T23:15:12Z', 
   ModificationTimestamp: '2012-04-13T23:15:12Z', n: 2},
  {RemindingTimestamp: '2012-04-12T23:15:12Z', 
   ModificationTimestamp: '2012-04-13T23:15:14Z', n: 3}
];

// Sort it
myArray.sort(function(a,b) {
  var x = toDate(a.RemindingTimestamp) - toDate(b.RemindingTimestamp);
  return x? x : toDate(a.ModificationTimestamp) - toDate(b.ModificationTimestamp);
});

// Just to show the result
function sa(o) {
  var result = [], t;
  for (var i=0; i<o.length; i++) {
    t = o[i]; 
      result.push(t.n);
  }
  alert(result);
}

sa(myArray); // 1,2,3,4

如果需要,可以扩展日期字符串到日期对象的转换以处理时区(仅对于符合ISO8601的字符串,使用时区缩写而不是实际偏移的字符串是不可靠的).

Answer 2

function compareObject(obj1, obj2){
    if(obj1.RemindingTimestamp > obj2.RemindingTimestamp)
        return - 1;
    if(obj2.RemindingTimestamp > obj1.RemindingTimestamp)
        return 1;

    // obj1.RemindingTimestamp == obj2.RemindingTimestamp

    if(obj1.ModificationTimestamp > obj2.ModificationTimestamp)
        return -1;
    if(obj2.ModificationTimestamp > obj1.ModificationTimestamp)
        return 1;

    return 0;
}

myObjects.sort(compareObject);

JSFiddle演示

资源:

• MDN:Array.sort()

Answer 3

自定义比较器采用以下形式:

myArray.sort(function(a,b){
  var m1=a1.RemindingTimestamp,
      m2=a2.RemindingTimestamp,
      n1=a1.ModificationTimestamp,
      n2=a2.ModificationTimestamp;
  return m1<m2 ? -1 : m1>m2 ? 1 :
         n1<n2 ? -1 : n1>n2 ? 1 : 0;
});

对于降序排序,交换<和>(或交换1和-1).

虽然您可以在每次需要时自行创建自定义比较器,但我创建了一个明确设计的方法,可以使用Schwartzian变换轻松地按多个条件进行排序(在某些情况下可能更快但内存更多):http:// phrogz.net/js/Array.prototype.sortBy.js

简而言之:

myArray.sortBy(function(obj){
  return [obj.RemindingTimestamp, obj.ModificationTimestamp];
}).reverse();

该reverse是有,因为你提到你想要一个降序排序.如果这两个RemindingTimestamp和ModificationTimestamp是数字,你可以做交替:

myArray.sortBy(function(obj){
  return [-obj.RemindingTimestamp, -obj.ModificationTimestamp];
});

以下是添加sortBy到数组的代码:

(function(){
  // Extend Arrays in a safe, non-enumerable way
  if (typeof Object.defineProperty === 'function'){
    // Guard against IE8's broken defineProperty
    try{Object.defineProperty(Array.prototype,'sortBy',{value:sb}); }catch(e){}
  }
  // Fall back to an enumerable implementation
  if (!Array.prototype.sortBy) Array.prototype.sortBy = sb;

  function sb(f){
    for (var i=this.length;i;){
      var o = this[--i];
      this[i] = [].concat(f.call(o,o,i),o);
    }
    this.sort(function(a,b){
      for (var i=0,len=a.length;i<len;++i){
        if (a[i]!=b[i]) return a[i]<b[i]?-1:1;
      }
      return 0;
    });
    for (var i=this.length;i;){
      this[--i]=this[i][this[i].length-1];
    }
    return this;
  }
})();

以下是文档中的更多示例:

var a=[ {c:"GK",age:37}, {c:"ZK",age:13}, {c:"TK",age:14}, {c:"AK",age:13} ];

a.sortBy( function(){ return this.age } );                                  
  --> [ {c:"ZK",age:13}, {c:"AK",age:13}, {c:"TK",age:14}, {c:"GK",age:37} ]

a.sortBy( function(){ return [this.age,this.c] } );                         
  --> [ {c:"AK",age:13}, {c:"ZK",age:13}, {c:"TK",age:14}, {c:"GK",age:37} ]

a.sortBy( function(){ return -this.age } );                                 
  --> [ {c:"GK",age:37}, {c:"TK",age:14}, {c:"ZK",age:13}, {c:"AK",age:13} ]


var n=[ 1, 99, 15, "2", "100", 3, 34, "foo", "bar" ];

n.sort();
  --> [ 1, "100", 15, "2", 3, 34, 99, "bar", "foo" ]

n.sortBy( function(){ return this*1 } );
  --> [ "foo", "bar", 1, "2", 3, 15, 34, 99, "100" ]

n.sortBy( function(o){ return [typeof o,this] } );
  --> [1, 3, 15, 34, 99, "100", "2", "bar", "foo"]

n.sortBy(function(o){ return [typeof o, typeof o=="string" ? o.length : o] })
  --> [1, 3, 15, 34, 99, "2", "100", "bar", "foo"]

注意在最后一个例子中(typeof this)发生的不一样 (typeof o); 有关更多详细信息,请参阅此帖

Answer 4

假设这两个属性都采用相同的可排序格式，下面是另一种深度排序方式ES6：

const comparingFunction = (a, b) => {
  if (a.property1 < b.property1) {
    return -1;
  }
  if (a.property1 > b.property1) {
    return 1;
  }

  if (a.property1 == b.property1) {
    if (a.property2 < b.property2) {
      return -1;
    }
    if (a.property2 > b.property2) {
      return 1;
    }
    return 0;
  }
};

myArrayOfObjects.sort(comparingFunction);

希望它对某人有帮助。