如何在javascript中使用变量定义变量？

Question

EDIT 2 : This is my first post on stock overflow and although I sometimes have some bad, questions to ask. i thought id at least fix the formatting considering I can not delete this.

I essentially wanted to automate variable creation , although at the time I did not not such things as arrays existed surprisingly.

I want to automate the creation of this variable

var l = createSprite(200,200);

I want to be able to define one variable , with another like this :

var count = 5;
var l + count = 1;
count++;
var l + count = 2;

var l=30 
var l + "foo" = 40`

if I were to run this, lfoo would be returned undefined. Why? Is this impossible? If so how can i automate defining variables?

Answer 1

You could take an object and use l as part of the key for the access.

• Object initializer
• Object
• Property accessor

 var l = 30 , object = { [l + "foo"]: 40 }; console.log(object[l + "foo"]); console.log(object);

Answer 2

You can't define variables like this. You have to define it through writing the absolute name for them. But to call them you can use window["l"+"foo"].

 var l = 40; var lfoo = 30; console.log(window["l"]+"...."+window["l"+"foo"]);

Answer 3

You could use window to declare global variables

var str = 'l' + 'foo';
window[str] = 40;
//Then you can access lfoo directly