从数组填充另一个数组 - Javascript

问题描述：

我想在JS中做的很简单（将一个数组的值分配给另一个数组），但不知何故，数组 bar 的值似乎没有受到影响一点都不

Very simple thing I am trying to do in JS (assign the values of one array to another), but somehow the array bar's value doesn't seem affected at all.

我尝试的第一件事当然是 bar = ar; - 没有用，所以我尝试手动循环...仍然无法正常工作。

The first thing I tried, of course, was simply bar = ar; -- didn't work, so I tried manually looping through... still doesn't work.

我没有理解Javascript的怪癖！请帮忙!!

I don't grok the quirks of Javascript! Please help!!



var ar=["apple","banana","canaple"];
var bar;


for(i=0;i<ar.length;i++){
    bar[i]=ar[i];
}
alert(ar[1]);

而且，这里是小提琴： http://jsfiddle.net/vGycZ/

And, here is the fiddle: http://jsfiddle.net/vGycZ/

（以上是简化。实际的数组是多维的。）

(The above is a simplification. The actual array is multidimensional.)

答

你的代码无法正常工作，因为你没有初始化 bar ：

Your code isn't working because you are not initializing bar:

var bar = [];

您也忘记申报 i 变量，这可能有问题，例如，如果代码在函数内， i 将最终成为一个全局变量（总是使用 var ：）。

You also forgot to declare your i variable, which can be problematic, for example if the code is inside a function, i will end up being a global variable (always use var :).

但是，你可以通过使用 slice 方法来创建第一个数组的副本：

But, you can avoid the loop, simply by using the slice method to create a copy of your first array:

var arr = ["apple","banana","canaple"];
var bar = arr.slice();

从数组填充另一个数组 - Javascript

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