PEP8 Bindings

Beginning with release 4.3 of PySimpleGUI, all methods and function calls have PEP8 equivalents. This capability is only available, for the moment, on the PySimpleGUI tkinter port. It is being added, as quickly as possible, to all of the ports.

As long as you know you're sticking with tkinter for the short term, it's safe to use the new bindings.

The Non-PEP8 Methods and Functions

Why the need for these bindings? Simply put, the PySimpleGUI SDK has a PEP8 violation in the method and function names. PySimpleGUI uses CamelCase names for methods and functions. PEP8 suggests using snake_case_variables instead.

This has not caused any problems and few complaints, but it's important the the interfaces into PySimpleGUI be compliant. Perhaps one of the reasons for lack of complaints is that the Qt library also uses SnakeCase for its methods. This practice has the effect of labelling a package as being "not Pythonic" and also suggests that this package was originally used in another language and then ported to Python. This is exactly the situation with Qt. It was written for C++ and the interfaces continue to use C++ conventions.

PySimpleGUI was written in Python, for Python. The reason for the name problem was one of ignorance. The PEP8 convention wasn't understood by the developers when PySimpleGUI was designed and implemented.

You can, and will be able to for some time, use both names. However, at some point in the future, the CamelCase names will disappear. A utility is planned to do the conversion for the developer when the old names are remove from PySimpleGUI.

The help system will work with both names as will your IDE's docstring viewing. However, the result found will show the CamelCase names. For example help(sg.Window.read) will show the CamelCase name of the method/function. This is what will be returned:

Read(self, timeout=None, timeout_key='__TIMEOUT__', close=False)

The Renaming Convention

To convert a CamelCase method/function name to snake_case, you simply place an _ where the Upper Case letter is located. If there are none, then only the first letter is changed.

Window.FindElement becomes Window.find_element

Class Variables

For the time being, class variables will remain the way they are currently. It is unusual, in PySimpleGUI, for class variables to be modified or read by the user code so the impact of leaving them is rarely seen in your code.