Variable name - invalid left-hand side in assignment

Question

I'm kind of new ... so go easy on me. This is what I want to do:

I have variables named:

var item1, item2, item3, etc.;

I want to use a For loop to asign values to the variables. Like this:

for(var i = 0; i < 5; i++){ item + (i+1) = arr[i] }

How can I do this without getting the Invalid left-hand side in assignment error?

Thank you.

If those variables are local, then there is no way to access them "dynamically". Nor should you. Whenever you have variables of the form `prefixX`, then you should use an array or object instead. Since you already seem to have an array, you should change the code that reads `itemX` to work with an array instead. And FYI, `item + (i+1)` will increase `i` by one and add the result to the value of the variable `item`. — Felix Kling, Jun 25 '13 at 07:57
I especially like [this answer](http://stackoverflow.com/a/6343596/218196): *"Q: What is the use of Dyanmic variables? A: For when people haven't heard of objects or arrays."* — Felix Kling, Jun 25 '13 at 08:14
I did, didn't I? Provided you with all sorts of information. — Felix Kling, Jun 25 '13 at 08:27

score 1 · Answer 1 · answered Jun 25 '13 at 07:59

1

Perhaps you could make use of a "namespace"/object like this:

var app={ item1: undefined, item2: undefined }
for(var i=1; i<3; i+=1) app["item"+i]=666;
console.log(app);

In this case, it is no "real" namespacing, but you could use it like that.

For more about Namespacing read this Article from Addy Osmani.

answered Jun 25 '13 at 07:59

Thomas Junk

Using an object is ok, but why talk about namespacing at all? It has nothing to do with this question/answer. – Felix Kling Jun 25 '13 at 08:08
Yes. As I said, it is no namespacing in the strict sense - more something than an initial step towards namespacing. In a wider sense it behaves like one. On the one hand you could say, "item1" is a property of "app" and on the other hand, you could think of it like "variable »item1« from the namespace »app«". – Thomas Junk Jun 25 '13 at 08:24
Well, yeah, you *can* use objects as namespaces, but this is a bit far fetched here IMO. If I was a beginner, I would find it rather confusing. Here you are using an object as a map, nothing more and nothing less. No need to make it overly complicated. – Felix Kling Jun 25 '13 at 08:26
Perhaps you're right ;) A bit far fetched. – Thomas Junk Jun 25 '13 at 08:29

score 0 · Answer 2 · answered Jun 25 '13 at 08:08

0

If it is a global variable, then you can do this:

var item1 = 5;
alert(window["item" + 1]);

answered Jun 25 '13 at 08:08

Balint Bako

2 Answers2