如何像开发人员控制台一样计算数组中的项

How to count the items in array like the developer console

本文关键字：计算 一样 数组 开发 何像 控制台      更新时间：2023-09-26

脚本：

vL1 = ["AB", "AB", "AB", "AB", "AB", "CS", "CS", "CS", "ND", "ND"];
vL2 = ["1",  "1",  "1",  "2",  "3",  "1",  "1",  "2",  "1",  "1"];
for(var i = 0; i < vL1.length; i++){
    thing = vL1[i] + " " + vL2[i];
    console.log(thing);
}

当我检查开发人员控制台时，我看到以下内容：

(3) AB 1
    AB 2
    AB 3
(2) CS 1
    CS 2
(2) ND 1

如何修改脚本，以便获得代码中出现AB和1或CS和1的次数，以便用于其他函数？

我只想知道vL1中表示的每个vL2的计数。关联vL1很重要，因为这将使我能够识别vL2，因为它不是唯一的。

您还可以执行以下操作；

var vL1 = ["AB", "AB", "AB", "AB", "AB", "CS", "CS", "CS", "ND", "ND"],
    vL2 = ["1",  "1",  "1",  "2",  "3",  "1",  "1",  "2",  "1",  "1"],
 result = vL1.reduce((p,c,i) => p[c] ? (p[c][vL2[i]] = p[c][vL2[i]] ? ++p[c][vL2[i]]
                                                                    : 1, p)
                                     : (p[c] = {[vL2[i]]: 1}, p), {});
console.log(result);

您可以将计数存储在对象中。此外，使用Array.prototype.reduce可以使使用索引变得更简单(例如，您不必手动处理索引的递增等(：

    vL1 = ["AB", "AB", "AB", "AB", "AB", "CS", "CS", "CS", "ND", "ND"];
vL2 = ["1",  "1",  "1",  "2",  "3",  "1",  "1",  "2",  "1",  "1"];
var counts = vL1.reduce(function(counts,vL1Element,index) {
  //initialize this index if it isn't set
  if(counts[vL1Element] == undefined) {
    counts[vL1Element] = {};
  }
  //set this count to 0 if it hasn't been set yet
  if (counts[vL1Element][vL2[index]] == undefined) {
    counts[vL1Element][vL2[index]] = 0;
  }
    counts[vL1Element][vL2[index]]++;
  return counts;
},{});
console.log(counts);

var obj={};
function log(a){
 if(obj[a]){
  obj[a]++;
 }else{
  obj[a]=0;
 }
 }

然后做：

log(thing);

在你的for循环内部，然后：

console.log(obj);

Obj现在包含：AB1:3；…

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