How Can I Share Global Variables Between Imported Python Modules?

Visibility of Global Variables in Imported Modules

In Python, global variables are scoped within a module, not globally across all modules. This can lead to confusion for developers attempting to share global variables between imported modules.

Problem:

Consider the following scenario: you have a module named "module1" that defines utility functions. These functions rely on a global variable "a" defined in the module where they are imported. Importing "module1" and attempting to call its functions results in a "global name 'a' is not defined" error.

Solutions:

There are several approaches to resolve this issue:

• Set the global variable in the importing module: This involves accessing the imported module's global namespace and setting the variable before calling its functions.
• Pass the global variable as an argument: When importing "module1," pass the global variable "a" as an argument to the module's functions. This allows the functions to access the variable without modifying the global namespace.
• Create a shared module: If the global variable is needed by multiple modules, create a separate module that serves as a shared repository for these variables. Import both the shared module and the modules that require access to the variables.

Additional Considerations:

• Avoid using from module import var for global variables. This creates a local variable and does not update the global variable when it is modified in the imported module.
• For truly global variables, consider using the builtins module (Python 3.x only) or implementing a custom global variable solution.

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