如何使用push子阵列？

I have 3 arrays like:

我有3个数组，如：

var arr1 = [];
var arr2 = [];
var arr3 = [];

//When I want to add something into array then I use
arr1.push("text");
arr2.push("text");

but is it possible to make something like the following example?

但是可以制作类似下面的例子吗？

//example:
var arr = [];

arr['group1'].push("text1");
arr['group2'].push("text2");
arr['group2'].push("textn");

//and then iterate like:

for(item in arr['group1'])
  console.log(item);

is it even possible to do something like that? I have tried but does not work.

甚至可以做那样的事情吗？我试过但不行。

4 个解决方案

#1

There's a fundamental misunderstanding though, arr is an array but you're using it as an associative array, which in JavaScript is better represented with an object {}. for...in is for objects, NOT arrays, the MDN has a warning note about it:

但是有一个根本的误解，arr是一个数组，但你将它用作一个关联数组，在JavaScript中用对象{}更好地表示。 for ... in for objects，NOT arrays，MDN有一个关于它的警告说明：

for..in should not be used to iterate over an Array where index order is important...

for..in不应该用于迭代索引顺序很重要的数组...

I would advice even if index is trivial to use a regular for loop or a forEach.

即使索引使用常规for循环或forEach，我也会建议。

Consider using the following, more appropiate approach.

考虑使用以下更合适的方法。

var obj = {
  group1: ['text1'],
  group2: ['text2'],
  group3: ['text3']
};

// pushing more strings
obj.group1.push('foo');
obj['group2'].push('baz');

#2

You're treating arr['group1'] as an array (by using .push()), but you haven't declared it as an array.

您将arr ['group1']视为一个数组（使用.push（）），但您尚未将其声明为数组。

var arr = [];

arr['group1'] = [];
arr['group2'] = [];
arr['group3'] = [];

arr['group1'].push("text1");
arr['group2'].push("text2");
arr['group2'].push("textn");

#3

It seems you're actually looking for Javascript Objects instead of arrays.
Also, you need to create these objects first.

看来你实际上是在寻找Javascript对象而不是数组。此外，您需要首先创建这些对象。

var obj = {group1:[],group2:[],group3:[]};

/* or
var obj = {};
obj.group1 = [];
*/

obj['group1'].push("text1");
// or obj.group1.push("text1");

#4

The for...in structure sets your for variable to the key, not the value. Assuming arr['group1'] is an array, this will work fine:

for ... in结构将变量设置为键，而不是值。假设arr ['group1']是一个数组，这将正常工作：

//example:
var arr = [];

arr['group1'].push("text1");
arr['group2'].push("text2");
arr['group2'].push("textn");

//and then iterate like:

for(item in arr['group1'])
  console.log(arr['group1'][item]);

#1