Software applications are developed in three repeating phases: understanding a problem, designing a solution, and implementing the solution. These phases repeat throughout the life of an application, refining and honing it until it is either optimal or obsolete.

In this chapter, we'll learn about the following topics:

• Introducing and analyzing a scenario in the workplace that will need a software solution
• Documenting the requirements of the solution
• Developing a design for a piece of software that implements the solution

Congratulations! Your Python skills have landed you a great data analyst job at ABQ AgriLabs. So far, your job is fairly simple: collating and doing simple data analysis on the CSV files sent to you daily from the lab's data entry staff.

There is a problem, though. You've noted with frustration that the quality of the CSV files from the lab is sadly inconsistent. Data is missing, typos abound, and often the files have to be re-entered in a time-consuming process. The lab director has noticed this as well and, knowing that you are a skilled Python programmer, she thinks you might be able to help.

You've been enlisted to program a solution that will allow the data entry staff to enter lab data into a CSV file with fewer mistakes. Your application needs to be simple and allow as little room for error as possible.

Now that you've assembled your data about the application, it's time to write up aspecification. Software specifications can range from very formal, contractual documents that include time estimates and deadlines, to a simple set of descriptions of what the programmer intends to build. The purpose of the specification is to give everyone involved in the project a point of reference for what the developer will create. It spells out the problem to be solved, the functionality required, and the scope of what the program should and shouldn't do.

Your scenario is rather informal and your application is simple, so you do not need a detailed formal specification in this case. However, a basic write-up of what you know will make sure that you, your boss, and the users are all on the same page.

With our specification in hand and our requirements clear, it's time to start designing our solution. We'll start with the form GUI component itself.

We're going to create a basic design for our form in the following three steps:

1. Determine the appropriateinput widget for each data field
2. Group together related items to create a sense of organization
3. Layout our widgets in their groups on a form sheet

Like all toolkits, Tkinter offers a variety ofinput widgets for different kinds of data. However, ttk offers additional widget types and enhances some (but not all!) of Tkinter's native widgets. The following table offers advice on which widgets...

In this chapter, you worked through the first two phases of application development: understanding the problem and designing a solution. You learned how to develop an application specification by interviewing users and examining the data and requirements, creating an optimal form layout for your users, and learned which widgets are available in Tkinter for dealing with different kinds of input data. Most importantly, you learned that developing an application doesn't begin with code, but with research and planning.

In the next chapter, you'll create a basic implementation of your designs with Tkinter and Python. We will get familiar with the Tkinter widgets required to create our form, build the form, and place the form within the application. We'll also learn how to make our form trigger callback actions and discover how to structure our code to ensure...