如何从多维数组构建一个简单的字符串？答案

【问题标题】：How to build a simple string from a multidimensional array?如何从多维数组构建一个简单的字符串？
【发布时间】：2013-08-24 05:54:48
【问题描述】：

基本上，我有一个多维数组，我需要将它构建成一个简单的字符串。

这是一个很简单的问题，虽然它已经困扰我很长一段时间了，因为我似乎无法确定它。

下面是一个示例，说明我的数组仅包含 3 个问题：

[["question1","answer1","answer2","answer3","answer4"],["question2","answer1","answer2","answer3","answer4"],["question3","answer1","answer2","answer3","answer4"]]

例如，D.rows[0][0] 将是“question1”，D.rows[2][3] 将是“answer3”，只是为了澄清。

下面是它必须如何保存到字符串中：

question1,answer1,answer2,answer3,answer4 
question2,answer1,answer2,answer3,answer4 
question3,answer1,answer2,answer3,answer4

每个元素之间必须有逗号，每个问题必须用换行符分隔。

这是我目前无法使用的：

var fullString;
for (i = 0; i < csvArray.length; ++i) 
{
    second = secondArray[i];
    for (j = 0; j < second.length; ++j) 
    {
        fullString += entry[j] + "'";
    }
    fullString += "\n";
}

提前致谢！

【问题讨论】：

标签： javascript for-loop multidimensional-array

【解决方案1】：

试试这个

var s,a=[["question1","answer1","answer2","answer3","answer4"],"question2","answer1","answer2","answer3","answer4"],["question3","answer1","answer2","answer3","answer4"]];
for(i=0; i < a.length; i++){
    s=(s)?s+"\n\r"+a[i].join():a[i].join();
}

jsfiddle example

在你自己的例子中：因为你要直接添加到fullString，它应该有一个空字符串作为值，否则你会在开头得到undefined。

var fullString="";

这部分second = secondArray[i];应该是

var second = csvArray[i];

同样，fullString += entry[j] + "'"; 应该是

fullString += second[j] + ",";

【讨论】：

@fizzix - 在 ecma 脚本规范中未指定 for in 循环中的迭代顺序 - 结果可能在不同的浏览器中有所不同，如果你在 ES3 中添加到数组原型，你也会得到 - 使用for(i=0; i
感谢@magyar1984 的通知，现在已经使用 ES5 一段时间了，并且倾向于忘记一些差异 ^^。但就我个人而言，我什至建议使用 spy-js 给出的答案

【解决方案2】：

一个班轮：

var result = [["question1","answer1","answer2","answer3","answer4"],["question2","answer1","answer2","answer3","answer4"],["question3","answer1","answer2","answer3","answer4"]].join('\r\n');

【讨论】：

【解决方案3】：

类似这样的：

var questionAnswerSet= { "question1" : [
{“答案1”：“价值”， “answer2”：“价值”， “answer3”：价值} ],
“问题2”：[
{“答案1”：“价值”， “answer2”：“价值”， “answer3”：价值} ], }

并像这样访问：

questionAnswerSet[0].answer2 // 问题一答案2

questionAnswerSet[1].answer2 // 问题二答案2

【讨论】：

抱歉，这完全没有意义吗？我相信我需要一个双循环来遍历数组中的每个元素。
我的数组可以有任意数量的条目吗？而且元素总是不同的......

【解决方案4】：

for (var i=0; i<yourArray.length; i++) { // iterate on the array
   var obj = yourArray[i];
   for (var key in obj) { // iterate on object properties
      var value = obj[key];
      console.log(value);
   }
}

【讨论】：

【解决方案5】：

如果你有这样的数组...

var arr = [["question1","answer1","answer2","answer3","answer4"],["question2","answer1","answer2","answer3","answer4"],["question3","answer1","answer2","answer3","answer4"]];

那么……

var strArr  =  arr.join(',');
var strLine =  arr.join('\n'); // string with line breaks.

会为你做的。

如果您希望每个问答块使用不同的字符串，那么...

var strJoinArr = [], strJoinLines = '';
for(var i = 0; i < arr.length; i++){
    strJoinArr.push(arr[i].join(','));
    strJoinLines += arr[i].join(',')+ '\n'; // string with line break
}

然后要访问每个部分，您可以使用索引，

例如，strJoinArr[2] 将返回 'question3,answer1,answer2,answer3,answer4'

更多关于.join() 更多关于.push()

【讨论】：

如何添加换行符？

【解决方案6】：

如果您打算更改分隔符或答案数量，这可能是您的解决方案。

var array = [["question1","answer1","answer2","answer3","answer4"],["question2","answer1","answer2","answer3","answer4"],["question3","answer1","answer2","answer3","answer4"]],
string = "";

for (var i = 0; i <= array.length - 1; i++) {
     string +=array[i].join(', ');
     string += "\n";
}

此外，对于这种结构的任何对象，以不太可读但有效的方式

string = array.join('\r\n');

【讨论】：