Ruby symbols are not garbage collected!? Then, isn't it better to use a String?

Question

If you create 10,000 strings in a loop, a lot of garbage collection has to take place which uses up a lot of resources.

If you do the same thing with symbols, you create objects which cannot be garbage collected.

Which is worse?

Answer 1

Seeing as symbols are almost always created via literals, there isn't much potential for a memory explosion here. Their behavior is pretty much required by their usage: every time you refer to a symbol, it's the same one.

Similarly, strings need to be unique in Ruby. This is due to the way they're used - text processing etc.

Decide which one to use depending on their semantics, don't optimize prematurely.

Answer 2

If you refer to the same symbol in your loop, then it doesn't have to recreate that object everytime i.e.

while i < 10000
  i += 1
  :im_using_this_symbol_here
end

Now if you use a string there instead, the string will be recreated 10K times. In general, use symbols in cases where you almost treat the literal like a constant or a key. A very good example for me would be

link_to "News", :action => 'news'

instead of

link_to "News", "action" => 'news'

action being re-used over and over again within your application.