Is declaring and assigning variable(s) during update a problem?

[Khari_Riviears]

Seem like because its normally a thing you do just once but now the program is creating the variable every frame is this now crazy inefficient and only ok cus the game is simple?

[Nina]

Hi Khari,

Could you please share an example? Creating and destroying variables in Update should not cause any issues, especially not if we don’t create millions over and over again.

[jbwb]

From:

    void Update()
    {
        float xValue = Input.GetAxis("Horizontal");
        float zValue = Input.GetAxis("Vertical");
        transform.Translate(xValue, 0, zValue);
    }

My understanding is: it’s not inefficient. A float is only 4 bytes. Creating 8 bytes locally to Update() each iteration should not cause performance problems unless your computer is a potato.

But let’s pretend he was creating a more expensive object, one that would cause a performance problem. In that case, C# has an excellent optimiser that would uplift any expensive local initializations. (read: this thread @ stackexchange, which I think is similar to your question).

And finally, just to throw mud on the subject, references to unity components or objects are usually cached @ Class scope and assigned @ Awake() or Start() because searching for them is an expensive operation that I’m not certain C# knows how to optimize.

So I guess my final answer is: if it’s a problem, do whatever is sensible.