Book Image

Learn Programming in Python with Cody Jackson

By : Cody Jackson
Book Image

Learn Programming in Python with Cody Jackson

By: Cody Jackson

Overview of this book

Python is a cross-platform language used by organizations such as Google and NASA. It lets you work quickly and efficiently, allowing you to concentrate on your work rather than the language. Based on his personal experiences when learning to program, Learn Programming in Python with Cody Jackson provides a hands-on introduction to computer programming utilizing one of the most readable programming languages–Python. It aims to educate readers regarding software development as well as help experienced developers become familiar with the Python language, utilizing real-world lessons to help readers understand programming concepts quickly and easily. The book starts with the basics of programming, and describes Python syntax while developing the skills to make complete programs. In the first part of the book, readers will be going through all the concepts with short and easy-to-understand code samples that will prepare them for the comprehensive application built in parts 2 and 3. The second part of the book will explore topics such as application requirements, building the application, testing, and documentation. It is here that you will get a solid understanding of building an end-to-end application in Python. The next part will show you how to complete your applications by converting text-based simulation into an interactive, graphical user interface, using a desktop GUI framework. After reading the book, you will be confident in developing a complete application in Python, from program design to documentation to deployment.
Table of Contents (14 chapters)

Launching Python programs

If you want to run a Python program, simply type python at the shell command prompt (make sure it's not Python's interactive prompt).

The code is a stand-in term for a generic program; don't try to actually run it because it won't work.

The following screenshot demonstrates how to call a Python program from the command line. This particular program simulates rolling a number of dice; the actual program will be discussed later in this book:

Launching a program

Files saved with the .py extension are called modules and can be called individually at the command line or imported into a program, similar to header files in other languages; we saw an example of this in the screenshot labeled Python calculator. If your program is going to import other modules, it is easiest to ensure they are all saved in the same directory on the computer, or you have to do some extra work to point to a different directory. More information on working with modules can be found in Chapter 2, Data Types and Modules, in the Importing modules section, or in the Python documentation.

Depending on the program, certain arguments can be added to the command line when launching the program. This is similar to adding switches to a Windows command prompt. The arguments tell the program what exactly it should do.

For example, perhaps you have a Python program that can output its processed data to a file rather than to the screen. To invoke this function in the program you simply launch the program like the following example—launching a Python program with arguments:

$ python -f /home/User/Documents

The -f argument is received by the program and calls a function that saves the data to the designated location (/home/User/Documents) within the computer's filesystem instead of printing it to the screen.