Code will not work as function but does in the main code. (Python, pygame)

Question

I have been experimenting with pygame and I have run into a problem. The code I have written with the intent of creating a timing based event, will only work outside of a function. Am I missing something?

def drop_obs(obs_list, timer):

    timer += clock.tick(60)/1000
    if timer >= 2:
        x_obs_pos = WIDTH/2
        y_obs_pos = random.randint(0, HEIGHT - block_size)
        obs_list.append([x_obs_pos, y_obs_pos])
        timer = 0

If I paste the code inside the main code it works however. (In regards to this code, the goal is just to append a new x and y position to an already existing list ever time the clock ticks)

Answer 1

Try passing pre-defined global variables as the arguments for the drop_obs() function

timer1 = 0 
list1 = [] #can be pre-emptied or pre-filled
[...] #the other part of code

def drop_obs(obs_list,timer):
    timer += clock.tick(60)/1000
    if time >=2:
        x_obs_pos = WIDTH/2
        y_obs_pos = random.randint(0,HEIGHT - block_size)
        obs_list.append([x_obs_pos, y_obs_pos])
        timer = 0

drop_obs(list1,timer1)

Also if x_obs_pos and y_obs_pos are local variables (ie they are defined in a function) then you need to globalize it by using the statement global x_obs_pos and global y_obs_pos