Jul 11, 2016 · Thus, the author of a module can use global variables in the module without worrying about accidental clashes with a user’s global variables. On the other hand, if you know what you are doing you can touch a module’s global variables with the same notation used to refer to its functions, modname.itemname.

Defining a variable on the module level makes it a global variable, you don't need the global keyword. The second example is correct usage. However, the most common usage for global variables are without using the global keyword anywhere. The global keyword is needed only if you want to reassign the global variables in the function/method.

Oct 3, 2013 · This has nothing to do with Python; global variables are bad in any programming language. However, global constants are not conceptually the same as global variables; global constants are perfectly harmless. In Python the distinction between the two is purely by convention: CONSTANTS_ARE_CAPITALIZED and globals_are_not.

May 12, 2013 · Actually, you can create a global variable inside a function using global. It's just a bad idea, because the variable won't exist until assigned to for the first time. The problem more broadly with your explanation is that you talk of "defining" variables. Python variables are only created on assignment; there isn't a separate definition. –

def test(): global a a = a + 10 print(a) Using the global keyword just tells the test where to look for a. With the first method, you can't modify the global variable a, because you made a copy of it and you're using the copy. In the second method, though, any changes you make in the function test() to a, will affect the global variable a.

Dec 30, 2009 · If you assign the variable without the global keyword then Python creates a new local var -- the module variable's value will now be hidden inside the function. Use the global keyword to assign the module var inside a function. Pylint 1.3.1 under Python 2.7 enforces NOT using global if you don't assign the var.

for those struggling with why this isnt working with variables assigned above your classes/functions, it has to do with the way python loads imports vs patches. To overcome this, move the patch into your tests: with mock.patch(module.variable, new_value): exceute_your_function_or_test –

Aug 30, 2015 · Omit the 'global' keyword in the declaration of coins outside the function. This article provides a good survey of globals in Python. For example, this code: def f(): global s print s s = "That's clear." print s s = "Python is great!" f() print …

def change(key,value): global aname global alist alist.append(key) aname.extend(value) I am using this inside a for loop and which is reading input in from a JSON and other .txt files and adding the keys and value to a list which is then used by another function to save to the database.

For example if they contain import global_variables as g Later on they can reference 'g.USER' to get the user ID. """ global USER import getpass USER = getpass.getuser() # End of global_variables.py Then in my main module I use this: import global_variables as g g.init()