Graphical User Interface with Python
Python is inherently a programming language ideal for data analysis, and it works well by simply entering commands and seeing the results immediately. For longer programs, or ones that are used frequently, the code is usually written into a file and then executed from the command line or as an element of a more complex set of scripted operations. However many users prefer a graphical user interface or "GUI" where mouse clicks, drop-down menus, check boxes, images, and plots access with the mouse and sometimes the keyboard. Python has that too, through a selection of tools that can be added to your code.
The most developed core component for this purpose is the Tk/Tcl library. In its most recent versions it provides a very direct way of running your programs within a GUI that is attractive, matches the native machine windows in appearance, and is highly responsive. While this is not the only one, it is a solid starting point and may be all you need. Later in this tutorial we will show you how to use Python running in background behind a graphical interface in a browser window which is another technique that is growing in capability as the browsers themselves gain computing power. However, the Tk library will allow you to build free-standing graphical applications that will run on all platforms on which Python runs.
A Tk Tutorial
An excellent starting point is the Tk documentation tutorial which will take you step by step through how to use this library in Python and in other languages. Work through this one first, and then return here and we will illustrated it with a few examples to show you how to use it in Physics and Astronomy applications.