Javascript 使用变量值调用数组元素
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Using a variable value to call an array element
提问by user1145643
I have a string variable which contains the name of an array. What I'd like to do is access an element of that array. And write it to another variable. How can I do this?
我有一个包含数组名称的字符串变量。我想做的是访问该数组的一个元素。并将其写入另一个变量。我怎样才能做到这一点？
var sample = new Array();
sample[0] = 'one';
sample[1] = 'two';
var arrayname = "sample";
var number = arrayname[1]; /// Something like this, although I realize this doesn't work for obvious reasons...
I've read other questions in regards to using an variable value as a function, but I didn't understand the approach or even if this would work for the above situation.
我已经阅读了有关将变量值用作函数的其他问题，但我不理解这种方法，或者即使这适用于上述情况。
Thanks in advance!!
提前致谢！！
采纳答案by Skyrim
This should do it:
这应该这样做：
var sample = new Array();
sample[0] = 'one';
sample[1] = 'two';
var arrayname = "sample";
var number = window[arrayname][1];
alert(number);
回答by Pointy
There's no universal way in JavaScript to do exactlywhat you've got set up there, but you canuse string variables to access object properties in a dynamic way.
JavaScript 中没有通用的方式来完全按照您在那里设置的方式进行操作，但是您可以使用字符串变量以动态方式访问对象属性。
var objArr = { array1: [], array2: [] };
Now you can use a variable with the value "array1" or "array2" to get at those arrays:
现在您可以使用值为“array1”或“array2”的变量来获取这些数组：
var name = "array2";
objArr[name].push(14);
What you cannotdo in JavaScript is access local variables by a dynamic name, or indirectly if you prefer. You can access globalvariables that way if you have a name for the global context, which in a browser is the windowobject:
什么，你不能在JavaScript中做的是一个动态域名访问的局部变量，或间接，如果你喜欢。如果您有全局上下文的名称（在浏览器中是对象），则可以通过这种方式访问全局变量window：
window[ name ].push(17);
However there's no way to get a similar name for a local scope.
但是，无法为本地范围获得类似的名称。
edit— @Neal points out (and is downvoted mercilessly) that eval()can do what you want, but a lot of people recommend staying far away from eval()unless it's absolutely unavoidable (which is really rare). I've trained myself to ignore it so well that I always forget about it when questions like this are asked (which is, oddly, quite often on SO, though in my programming practice I never find myself wanting to do this).
编辑-@Neal 指出（并且被无情地拒绝）eval()可以做你想做的事，但很多人建议远离，eval()除非它绝对不可避免（这真的很少见）。我已经训练自己很好地忽略它，以至于在被问到这样的问题时我总是忘记它（奇怪的是，在 SO 上经常出现这种情况，尽管在我的编程实践中，我从来没有发现自己想要这样做）。
回答by jabclab
You could use something like:
你可以使用类似的东西：
var arrayName = "sample",
number = window[arrayname][1];
回答by Naftali aka Neal
I mean you can use eval, but it is not the best approach:
我的意思是你可以使用 eval，但这不是最好的方法：
eval("var arrayname = sample");
var number = arrayname[1];
Why not just do:
为什么不这样做：
var arrayname = sample;
var number = arrayname[1];
回答by Grooveek
If it's in the global scope, you can access your array by doing
如果它在全局范围内，您可以通过执行访问您的数组
var sample = new Array();
sample[0] = 'one';
sample[1] = 'two';
var arrayname = "sample";
var number = (window[arrayname])[1]
回答by itea
var sample = new Array();
sample[0] = 'one';
sample[1] = 'two';
var obj = {"sample": sample}
var arrayname = "sample";
var number = obj[arrayname][1];
回答by Sergey Kudriavtsev
Out of my head...
意料之外...
First declare some global variable
首先声明一些全局变量
var buf;
Then
然后
var sample = new Array();
sample[0] = 'one';
sample[1] = 'two';
var arrayname = "sample";
eval('buf=' + arrayname + ';');
var number = buf[1];
Damn undesirable way but does what you want...
该死的不受欢迎的方式，但做你想做的......
