如何计算数组中的重复值并存储在数组中

David 发表于 Dev

大卫

我有一些对象数组，而数据却很少。我的输入就像：

我的实际代码是：

buildcount: function(store2){
   var datacount = store2.data.items;
    for(var i=0; i<datacount.length; i++){
        var x = datacount[i].data
},

从商店这里，我正在获取x，它是对象的数组，每个对象都有

obj{
    STU: "Study1", SUB: "Subject1", EXL: "Yes"}
}

Object {STU: "Study1", SUB: "Subject1", EXL: "Yes"}
Object {STU: "Study1", SUB: "Subject1", EXL: "Yes"}
Object {STU: "Study2", SUB: "Subject1", EXL: "Yes"}
Object {STU: "Study3", SUB: "Subject1", EXL: "Yes"}
Object {STU: "Study1", SUB: "Subject1", EXL: "Yes"}
Object {STU: "Study3", SUB: "Subject1", EXL: "Yes"}
Object {STU: "Study3", SUB: "Subject1", EXL: "Yes"}
Object {STU: "Study2", SUB: "Subject1", EXL: "Yes"}

我想计算所有唯一元素，并与count一起存储在数组中。在javascript中。

输出： object {"Study1 : 3", "Study2" : 2, "Study3":4}

内纳德·弗拉卡（Nenad Vracar）

你可以做到这一点 reduce

var ar =  [{"STU":"Study1","SUB":"Subject1","EXL":"Yes"},{"STU":"Study1","SUB":"Subject1","EXL":"Yes"},{"STU":"Study2","SUB":"Subject1","EXL":"Yes"},{"STU":"Study3","SUB":"Subject1","EXL":"Yes"},{"STU":"Study1","SUB":"Subject1","EXL":"Yes"},{"STU":"Study3","SUB":"Subject1","EXL":"Yes"},{"STU":"Study3","SUB":"Subject1","EXL":"Yes"},{"STU":"Study2","SUB":"Subject1","EXL":"Yes"}]

var result = ar.reduce(function(o, e) {
  return o[e.STU] = (o[e.STU] || 0) + 1, o
}, {});

console.log(result)

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