[Tutor] invalid literal for int error in Game loop

[Prasad, Ramit]

Ciaran Mooney wrote:
> Sent: Thursday, December 20, 2012 3:35 PM
> To: d at davea.name
> Cc: tutor at python.org
> Subject: Re: [Tutor] invalid literal for int error in Game loop
> 
> Thanks for the feedback.
> 
> Steve, If I set the FPS to a default of say 30, the game seems to run at this default FPS=30 regardless of the
> key pressed in the function.
> 
> Dave, If I remove the the default value at the start of the function and add it to elif in the loop I get the
> following error:
> 
> 
> Traceback (most recent call last):
>   File "/Users/callanmooneys/Desktop/Pythoin Programmes/Aliens Game/dodger ver 3 instructons.py", line 139, in
> <module>
>     FPS = difficultyLevel()
>   File "/Users/callanmooneys/Desktop/Pythoin Programmes/Aliens Game/dodger ver 3 instructons.py", line 50, in
> difficultyLevel
>     return FPS
> UnboundLocalError: local variable 'FPS' referenced before assignment

If you read Dave's comment a little closer you will see that
he suggests adding an *else* block not another elif. 

(pseudocode)
if key == b:
    FPS = 30
elif key == m:
    FPS = 60 
elif key == h:
    FPS = 120
else:
    FPS = 15 # or whatever default value you want

> 
> 
> I wondered if i could set FPS to nether a string or integer and just declare it by setting FPS=None but I get
> the following error:
> 
> Traceback (most recent call last):
>   File "/Users/callanmooneys/Desktop/Pythoin Programmes/Aliens Game/dodger ver 3 instructons.py", line 301, in
> <module>
>     mainClock.tick(FPS)
> TypeError: a float is required

The else clause prevents FPS from being anything other than a number.
You can choose to predefine FPS or just let the if/else tree take
care of defining it.

> 
> Cheers
> Ciaran
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