A Quick Tour

Let's take a super-brief tour around PySimpleGUI before digging into the details. There are 2 levels of windowing support in PySimpleGUI - High Level and Customized.

The high-level calls are those that perform a lot of work for you. These are not custom made windows (those are the other way of interacting with PySimpleGUI).

Let's use one of these high level calls, the popup and use it to create our first window, the obligatory "Hello World". It's a single line of code. You can use these calls like print statements, adding as many parameters and types as you desire.

import PySimpleGUI as sg

sg.popup('Hello From PySimpleGUI!', 'This is the shortest GUI program ever!')

Or how about a custom GUI in 1 line of code? No kidding this is a valid program and it uses Elements and produce the same Widgets like you normally would in a tkinter program. It's just been compacted together is all, strictly for demonstration purposes as there's no need to go that extreme in compactness, unless you have a reason to and then you can be thankful it's possible to do.

import PySimpleGUI as sg

event, values = sg.Window('Get filename example', [[sg.Text('Filename')], [sg.Input(), sg.FileBrowse()], [sg.OK(), sg.Cancel()] ]).read(close=True)

The Beauty of Simplicity

One day I will find the right words, and they will be simple. ― Jack Kerouac

That's nice that you can crunch things into 1 line, like in the above example, but it's not readable. Let's add some whitespace so you can see the beauty of the PySimpleGUI code.

Take a moment and look at the code below. Can you "see" the window looking at the layout variable, knowing that each line of code represents a single row of Elements? There are 3 "rows" of Elements shown in the window and there are 3 lines of code that define it.

Creating and reading the user's inputs for the window occupy the last 2 lines of code, one to create the window, the last line shows the window to the user and gets the input values (what button they clicked, what was input in the Input Element)

import PySimpleGUI as sg

sg.theme('Dark Blue 3')  # please make your creations colorful

layout = [  [sg.Text('Filename')],
            [sg.Input(), sg.FileBrowse()], 
            [sg.OK(), sg.Cancel()]] 

window = sg.Window('Get filename example', layout)

event, values = window.read()
window.close()

Unlike other GUI SDKs, you can likely understand every line of code you just read, even though you have not yet read a single instructional line from this document about how you write Elements in a layout.

There are no pesky classes you are required to write, no callback functions to worry about. None of that is required to show a window with some text, an input area and 2 buttons using PySimpleGUI.

The same code, in tkinter, is 5 times longer and I'm guessing you won't be able to just read it and understand it. While you were reading through the code, did you notice there are no comments, yet you still were able to understand, using intuition alone.

You will find this theme of Simple everywhere in and around PySimpleGUI. It's a way of thinking as well as an architecture direction. Remember, you, Mr./Ms. Developer, are at the center of the package. So, from your vantage point, of course everything should look and feel simple.

Not only that, it's the Pythonic thing to do. Have a look at line 3 of the "Zen of Python".

The Zen of Python, by Tim Peters

Beautiful is better than ugly . Explicit is better than implicit . Simple is better than complex.
Complex is better than complicated.
Flat is better than nested.
Sparse is better than dense.
Readability counts.
Special cases aren't special enough to break the rules.
Although practicality beats purity.
Errors should never pass silently.
Unless explicitly silenced.
In the face of ambiguity, refuse the temptation to guess.
There should be one-- and preferably only one --obvious way to do it.
Although that way may not be obvious at first unless you're Dutch.
Now is better than never.
Although never is often better than right now.
If the implementation is hard to explain, it's a bad idea.
If the implementation is easy to explain, it may be a good idea.
Namespaces are one honking great idea -- let's do more of those!

I just hope reading all these pages of documentation is going to make you believe that we're breaking suggestion:

If the implementation is hard to explain, it's a bad idea.
If the implementation is easy to explain, it may be a good idea.

I don't think PySimpleGUI is difficult to explain, but I am striving to fully explain it so that you don't do this:

In the face of ambiguity, refuse the temptation to guess.

Sometimes you can guess and be fine. Other times, things may work, but the side effects are potentially significant. There may be a much better way to solve a problem - Log an Issue on GitHub!