Joining arrays
Hi, I'm using Unity but I don't think it's important.
I have a list of object, on which I want to call a method which returns a regular array (struct[]) which can be quite big.
Then I want to join all those arrays into a singular array. That big array will be generated only once, not modified and used for grabbing a random entry from that array multiple times.
As I'm not that experienced in optimizing c#:
1. Is there any advantage in using array here instead of List<T> which I feel is easier to work with?
2. What's the best way to join those arrays into singular one?
So far I'm doing it like that, but I think it is not optimal as I create new array for each iteration?
6 Replies
The performance difference in using a
List<> instead of an array is negligible, especially with the overhead of an entire game engine in the background.
However, if you plan on just keeping a selection of objects but not adding/removing to it regularly, it's better to use a regular array.
What you have right now seems fine. Maybe use LINQ if you want more optimization.I feel time performance is not as important as memory performance, I fear Garbage Collector stepping in to free those arrays and dipping one frame.
But I guess it will happen only once anyway
If this is at process startup you don't really need to optimize it. A small point: you should use
Array.Empty<T> instead of zero length arrays.Okay, I had to do some operations on those structs in the end I used a List and did nested foreach with .Add()
Not entirely, even if I do it at the start (and not when loading level for example), the next GC cycle may happen in 20 secends, so 20 seconds after starting the game the player will get a dip
Ephemeral GCs should clean it up much faster than that and I don't think it will show up at all.
Optimization isn't needed at this point. Unless you're dealing with a large amount of elements in the list.
Based on what we see right now, it's perfectly fine.