Python Button Dictionary Case Statement

What/Why

There is a technique in Python to use a dictionary in place of a case statement ( which in any case Python does not have ). This is a cool technique that can both make code faster and easier to maintain. I have also found that it is particurlarly useful with Tkinter to build GUIs. This page will give a little introduction and link to some example code.

How

A Case Statement

A case or switch statement in other languages may look something like this:

    ( something like this, I just made it up )
    switch on case A
         case "one"
               call sub_1()
         case "2"
             call sub_1()
     end switch

So when executed if A == "one" then sub_1 is called .......

Python Dict Approach

Assume we have build a dictionary something like

   case_dict   = { "one": sub_1,  "2": sub_2,  }

Then we can call the subroutine ( the switch case like statement )

   case_dict[ A ]()

It is really simple, supports very large number of cases, and is very fast.

With Tkinter Buttons

When we build buttons we can specify a command for the button. The idea we use here is to have all buttons call one subroutine with the button as an argument. That function then uses a dictionary to use a case dictionary to call the function we actually want. Doing this seems to require a little trick with a lambda function that I will describe only by showing you the code. You can find and read this at github [[]]. Read it, try it out, if you want let me know how you feel about it.