Issues with global scope

[Rogal Dorn]

How can you access global scope inside a function?
Here's a basic example of my issue. index is only scoped to increment() so I can't modify it from inside a function

index = 0

def increment():	
	index += 1

while True:
	print(index)
	increment()
	print(index)

Both print statements will output 0 instead of the before and after incrementing

[owenz]

From what I understand of the chomped down version of python there you would have to do something like the following.

index = 0

def increment(arg):
    return arg + 1
    
for i in range(100):
    if index % 10 == 0:
        quick_print(index)
    index = increment(index)

It seems the scoping rules are much stricter than in regular python. So you would have to do something like this if you want to have that particular variable in scope to work on it.

[Rogal Dorn]

That's not really usable for my use case.

The Solution

The solution it seems is to use a dictionary to store your globals, I missed the Name Scopes doc which says to do:

globals = {
	"index":0
}

def increment():	
	globals["index"] += 1

while True:
	print(globals["index"])
	increment()
	print(globals["index"])

So reference types are global but value types aren't

[befana666]

thx i was breaking my head over this

[Lynsis]

global variables only need to be placed in the "main" function window so you would need a new window for testing that that you have the global and the function in.

i.e

#Global variables
Index = 0


#Function calls
increment()
 

[Rogal Dorn]

Originally posted by Lynsis:

global variables only need to be placed in the "main" function window so you would need a new window for testing that that you have the global and the function in.

i.e

#Global variables
Index = 0


#Function calls
increment()
 

The name of the window shouldn't matter. And if you try that code you'll see it doesn't work

[TerroFlys]

Originally posted by Rogal Dorn:

That's not really usable for my use case. The solution it seems is to use a dictionary to store your globals, I missed the Name Scopes doc which says to do:

globals = {
	"index":0
}

def increment():	
	globals["index"] += 1

while True:
	print(globals["index"])
	increment()
	print(globals["index"])

So reference types are global but value types aren't

Thanks! I did not know Dictionaries would work! You're a life saver!
It does irritate me that we cannot modify global variables though, that should be in the game for sure.

[󠀡]

So you just can't use global variables until you have dictionaries unlocked?! What a nuisance.

Nevermind... You can use global variable IF they are declared in the "main" window but not anywhere else..

[Rogal Dorn]

Originally posted by 󠀡:

So you just can't use global variables until you have dictionaries unlocked?! What a nuisance.

Nevermind... You can use global variable IF they are declared in the "main" window but not anywhere else..

I don't know where that's working for you, but for me, and according to the docs that doesn't work.
If you define a variable in a window and have other code in the scope of that window then it will work, but then that's not a global. As soon as you add a function and try to modify that variable it'll error as a new variable is created in the scope of that function. You can disable the error but it won't function the way you think it would.

Meaning the output of this code...:

num = 0

def increment():
	num += 1
	
def test():
	num += 1
	print(num)
	increment()
	print(num)

test()
print(num)

Is:

1
1
0

Instead of:

1
2
2

[Mr. Koala Gun]

This has also been a pain point for me in trying to make a more complex set of functions for the maze solve. I can't even use dictionaries yet because I have to solve the maze first :(. Adding the global keyword would be a huge help.

[DarkQuiet]

Seems like each function call get not reference or pointer but copy of global variable thats so
♥♥♥♥♥♥♥ stupid

[THC R4wizard]

If you don't have dictionaries yet, you can do something similar with arrays:

state = [
   0,  # [0]: counter (by 5)
   0,  # [1]: counter (by 2)
   0,  # [2]: counter (sum)
]

def test():
    state[0] += 5
    state[1] += 2
    state[2] = state[0] + state[1]

[Mr Tree Frog]

The only way I was able to get globals to work (ish) was to return the value which actually turned out to make more spaghetti code. Part of my maze issue was I was passing values around and it the values were not updating properly.

It definitely failed more than it worked. I was pondering to see if I could get a class to work but decided not to dive into Python classes and refactor my problem with the tools I knew was there.