Question

I am making a drawing program in python with pygame right now. The interface is supposed to be vimesque, allowing the user to control most things with key presses and entering commands. I want to allow live binding of the buttons; the user should be able to change which keycode corresponds to which function. In my current structure, all bindings are stored in a dictionary of functions to keycodes, ‘bindingsDict.’ Whenever the main loop receives a KEY_DOWN event, I execute:
bindingDictkeyCode
Where keyCode is stored as an integer.
This works, but it seems to be taking a lot of time and I am having trouble thinking of ways I could optimize.
Does anyone know the big O run time of dict look ups? I assumed because it hashed it would run in ln(n) but there’s a huge difference in performance between this solution and just writing a list of if statements in the mainloop (which does not allow for dynamic binding).

Answer 1

It is rather unlikely that dictionary search for response to a user event would cause any noticeable delay on the program. There is something going wrong in your code.

Btw, dict and set search in Python is O(log(1)) – but for 105 keys, or even, if you count modifiers applied, about 1000 different keybindngs could be searched in linearly (that is, if the search was O(N) ) without a noticeable delay, even on a 5 year old (desktop) CPU.

So, just post some of your code if you want a solution for your problem. (reading the comments I’ve noticed you found something else that seems to be responsible already)