Question

我有一个数组

var arr = ["2:6", "2:3", "1:1", "1:2", "3:1"];

（这是javascript）; 我不知道如何将此数组转换为输出：

["2:6,3", "1:1,2", "3:1"];

你可以帮助我吗？

Answer 1

看起来您想要将具有相同初始数字的列表元素组合在一起。此代码将为您提供关联数组{"1":"1,2","2":"6,3","3§:"1"}作为输出：

   var arr = ["2:6", "2:3", "1:1", "1:2", "3:1"];
   var hist = {};
   arr.map( function (a) { b=a.split(":");c=b[0]; if (c in hist) hist[c]=hist[c].concat(","+b[1]); else hist[c] = b[1]; } );
   alert(JSON.stringify(hist));

另见JavaScript Group By Array

Answer 2

var interm = {}, output = [], regx = /(\d+):(\d+)/;
arr.forEach(function(x) {var y = regx.exec(x); if (y[1] in interm) interm[y[1]].push(y[2]); else interm[y[1]] = [y[2]]});
Object.keys(interm).map(function(x) { output.push(x + ":" + interm[x].join(',')) });

console.log(output);

[ '1:1,2', '2:6,3', '3:1' ]

这与使用正则表达式和forEach的速度方面的转换相差甚远，但它相当简洁，你没有提到你需要任何特别快的东西。

Answer 3

请参阅 LINK..

或申请以下代码......

HTML代码......

<input type='button' id='s' value='test' onclick="test()"/>

JQuery代码......

function test() {

    var arr = ["2:6", "2:3", "1:1", "1:2", "3:1"];
    var resultStr = "";

    for (i = 0; i < arr.length; i++) {

        if (i <= arr.length - 2) {
            var a = arr[i + 1].split(":");
            if (a.length > 0) {
                resultStr += arr[i] + ',' + a[1] + ' | ';
            }
        } else {
            var str = arr[i];
            resultStr += arr[i];
        }
        i++;
    }

    alert(resultStr);
}

Answer 4

您的输出看起来很像地图。我会把它写成：

{
  2 : [ 6, 3 ],
  1 : [ 1, 2 ],
  3 : [ 1 ]
}

要获取该映射，我将迭代数组，提取键和值，然后将值添加到正确的数组中，确保在尚未创建的情况下创建它。

var arr = ["2:6", "2:3", "1:1", "1:2", "3:1"];
var map = {};
arr.forEach(function(item){
  var split = item.split(':');
  if (!map[split[0]]) map[split[0]] = [split[1]];
  else map[split[0]].push(split[1]);
});

显然，从我的地图中你可以很容易地得到你想要的阵列：

var result = [];
for (var key in map) {
  if (map.hasOwnProperty(key)) // best practice
    result.push(key+':'+map[key]);
}

console.log(result); // ["1:1,2", "2:6,3", "3:1"]

一个注意事项：它没有你所做的相同顺序的项目，但可以通过迭代原始数组来获取密钥而不是使用for..in来轻松修复：

var result = [];
arr.forEach(function(item){
  var key = item.split(':')[0];
  if (map[key]) {
    result.push(key+':'+map[key]);
    delete map[key]; // destroys the map!
  }
});

console.log(result); // ["2:6,3", "1:1,2", "3:1"]

解决方案2（无中间地图）：

此解决方案具有O（n ^ 2）复杂度：

var arr = ["2:6", "2:3", "1:1", "1:2", "3:1"];

var result = [];
for (var i=0; i<arr.length; i++) {
  if (!arr[i]) continue;
  var key = arr[i].split(':')[0];
  var values = [];
  for (var j=i; j<arr.length; j++) {
    var split = arr[j].split(':');
    if (split[0] === key) {
      values.push(split[1]);
      arr[j] = undefined; // destroys the original array
    }          
  }
  result.push(key + ':' + values);
}

console.log(result); // ["2:6,3", "1:1,2", "3:1"]

Answer 5

以下是JSFiddle

的工作示例

以下示例代码，

var arr = ["2:6", "2:3", "1:1", "1:2", "3:1"];
var tdarray = {};
var newarray = [];

for(var i=0;i<arr.length;i++){
    var data = arr[i].split(":");
    var found = false;
    for(var key in tdarray){
        if(data[0]==key){
            found = true;
            break;
        }
    }
    var list=[];
    if(found){
        list = tdarray[data[0]];
    }
    list.push(data[1]);
    tdarray[data[0]] = list;
}
for(key in tdarray){   
    var data = key + ":" + tdarray[key].join();
    newarray.push(data);
}

console.log(newarray);

Answer 6

另一种可能的解决方案......

var arr = ["2:6", "2:3", "1:1", "1:2", "3:1"], alreadyUsedNumbers = [];
for (var i=0; i < arr.length; i++) {
   var key = arr[i].split(":")[0], value = arr[i].split(":")[1];

   if (alreadyUsedNumbers.indexOf(key) >= 0) {
     for (var j=0; j < i; j++) {
        if (arr[j].indexOf(key) == 0) {
           arr[j] += ","+value;
           arr.splice(i, 1)
           i--;
           break;
        }
     }
   } else {
       alreadyUsedNumbers.push(key);
   }
}
console.log(arr);

...享受。

Answer 7

var arr = ["2:6", "2:3", "1:1", "1:2", "3:1", "4:6", "3:4"];
var output = new Array();
var outputString = "[";

for(var i=0; i<arr.length; i++)
{
    var index = arr[i].indexOf(":");
    var firstNr = arr[i].substring(0,index);
    var secondNr = arr[i].substring(index+1,arr[i].length);

    var outputPart = firstNr + ":" + secondNr;
    var j = i+1;
    while (j<arr.length)
    {
        var index2 = arr[j].indexOf(":");
        var firstNr2 = arr[j].substring(0,index2);
        var secondNr2 = arr[j].substring(index2+1,arr[j].length);
        if (firstNr == firstNr2)
        {   
            outputPart +=  "," + secondNr2;  
            arr.splice(j,1);
        }
        else
            j++;
    }
    output.push(outputPart);
}
for(var k=0; k<output.length; k++)
    outputString += "'" + output[k] + "' ";
outputString += "]";
alert(outputString);

在这里演示：http://jsfiddle.net/er144/QYca2/

javascript字符串转换

7 个答案: