Using Array Join for String Concatenation

Question

Attempting using Array.join for string concatenation, but the following is causing FF to choke:

var tmp = ["disco","dance"];
for (i = 0; i<tmp.length; i++) {
  tmp.push(piece);
  alert(tmp[i]);
}
str = tmp.join(''); 
return str;

Would someone enlighten my usage?

What's the problem? What error do you get? What is str set to when this is done? — gen_Eric
– gen_Eric, Commented Aug 30, 2011 at 17:35

gilly3 · Accepted Answer · 2011-09-02 16:09:11Z

3

You've got an infinite loop. Every iteration increases the length of tmp, so i will never be greater than tmp.length. Maybe this is what you want:

var tmp = ["disco","dance"];
var len = tmp.length;
for (i = 0; i < len; i++) {
  tmp.push(piece);
  alert(tmp[i]);
}
str = tmp.join(''); 
return str;

Edit: Or if piece doesn't really mean anything, just skip the for loop altogether:

var tmp = ["disco","dance"];
str = tmp.join(''); 
return str;

edited Sep 2, 2011 at 16:09

answered Aug 30, 2011 at 17:38

gilly3

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2 Comments

Wasabi Over a year ago

Was my interpretation of the following example in err? aymanh.com/…

gilly3 Over a year ago

What is piece and where does it come from? The example shown demonstrates building up a string into an Array and then joining it. But, it doesn't show where the elements of the array should come from - that part is left to you and your specific needs. If you already have an array of strings, there is no need for a for loop, you can just call .join() on your array.

cdhowie · Accepted Answer · 2011-08-30 17:44:45Z

1

I'm not sure what you're trying to do with the loop. This, however, works:

var tmp = ["disco","dance"];
var str = tmp.join(''); 
return str; // Returns "discodance"

...which is just your original code without the loop. I suspect any trouble that you're having has to do with that loop.

edited Aug 30, 2011 at 17:44

cdhowie

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answered Aug 30, 2011 at 17:35

FishBasketGordo

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