Building programs with python

Python tutorial for total beginners: Build a project from scratch

If you are a coding novice and want to start your coding journey, you’ve probably heard of Python. Python is one of the most popular language out there, and it continues to rise in popularity in demand. It’s an ideal language because it’s intuitive and simple.

Today, we will go through a Python beginner’s tutorial and build a simple dice rolling project step-by-step. Most Python tutorials jump into libraries right away, but you need a solid understanding of the basic syntax first.

We will discuss the basics of Python that you’ll use throughout your career. No prerequisite knowledge is required, but to be most successful with this article, a basic understanding of programming is helpful. For a quick introduction or refresher, check out our Absolute Beginner’s Guide to Programming.

Today we will cover:

Become a Python developer for free.

Get a handle on the basics of Python and learn how to build your own projects.

What is Python?

Python is a general purpose programming language that was first developed in 1990. It is one of the most popular programming languages around the world. The term “general-purpose” means that Python can be used for a variety of applications and uses.

Python is very intuitive and easy to use. Python is not only easy to pick up, but it is beloved by developers around the world.

Python can be used for things like:

• Web and mobile app development
• Mathematical analysis
• Processing big data and data science
• Desktop apps and software development
• Writing system scripts
• Video game development

Properties of Python

Python is strongly typed, which means that the type of data in your program is enforced. Python is also object-oriented, which means that all the elements of your programs are object you can act upon and manipulate.

Like many programming languages, Python is also case sensitive. This means that capitalized letters are recognized as different elements than lowercase letters, i.e. token and TOKEN are different variables. Lastly, Python is dynamically and implicitly typed. This means that a data type is enforced when we run the program.

Popularity of Python

Python remains one of the most popular programming languages around the world. In the 2020 StackOverflow survey, it ranks 1st for most popular language and 1st the most wanted language.

One reason Python is so popular is that important frameworks are written in Python, most notably machine learning frameworks. This means that Python’s popularity isn’t going anywhere, especially as data science become more commonplace across industries. Learning this language is an important step for becoming a professional programmer.

Hello World in Python

By now, we’ve learned the basics properties of Python. We are now ready to see some code. Whenever we learn a new language, it is an age-old tradition to start by displaying the text “Hello World” on the screen.

Since Python is one of the most readable languages out there, we can print data on the terminal by simply using the print statement.

Whatever we need to print is encapsulated in the parentheses following the print keyword, which is a command to the computer to print the text. Take a look and then try it yourself with the code tab.

Источник

Creating Python Programs

After reading the Python tutorial so far, you should have a basic understanding of Python and the REPL. Even though the latter can be very useful, you probably noticed in the last example that the REPL has its limits. It’s nice for quick experiments, but:

• It’s really hard to enter more than a few lines
• It’s hard to go back to previous lines
• There’s no syntax highlighting
• We can’t store our programs and re-use them later on

If we want to store our programs and use a decent editor, we need to simply:

No worries, we’ll go over it step by step.

1. Create a Python file

We need to create a so-called plain text file, meaning there’s nothing special about this file. It’s just text. Sounds simple, but it’s not. For example, if you start Word or a similar program, enter some text, and save it, you don’t end up with plain text.

Text processing software like Word will add all kinds of extra codes to define the markup, allow for images to be included, etcetera. It looks a little like HTML, in fact, which is used to create websites (see this HTML tutorial for an introduction).

So what should we use?

If you’re on Windows, try Notepad. It’s a plain text editor that does not add any markup. It’s a horrible way to create Python programs, but we’ll explore better options later on.

If you’re on Linux, you could open a terminal and try a text editor like nano or vim (the last one is hard to use if you haven’t read the manual, though). Many Linux installations include a GUI text editor too, like gedit.

MacOS comes with a program called TextEdit.

2. Enter the code

Now it’s time to enter some code. We’ll keep it super simple for now. Just enter something like:

On Windows, it should look like this:

3. Save the file

Save the file. The most important thing to look out for is the file extension. Python files end with the .py extension. Call your file helloworld.py . In Notepad, you need to click the dropdown list called ‘Save as type’ and select All files (*.* ):

4. Execute a Python program file

Now that you saved the file, we can execute it. There are two options, and most often you want to go for option one:

1. Open a terminal or command prompt, go to the file’s directory, and execute it with the python3 command
2. Find the file with Windows explorer, right click, open with ‘Python 3.X’.

If you try option two, you’ll find out that the program flashes on the screen shortly, and you won’t see the output because the window closes itself directly after the text is printed to the screen. So now you know why you want option one! If you create more advanced programs that keep running instead of quitting directly, option two can be an OK way to start a Python script.

Note: I’ll demonstrate using Windows, but this works the same on Linux and MacOS. Instead of opening a Command Prompt or Windows Terminal, you open a MacOS terminal or Linux terminal.

1. Open the start menu and type ‘Command Prompt.’ It might be named differently if your OS is configured with another language than English. Hint: Create a new profile with English settings. It may be helpful because most examples on the web and in books assume English settings.
2. cd to the directory where you stored your file. In my case, it’s C:\python.land
3. Run the program with the command python3 helloworld.py

The output should look like this:

Congrats, You did it. You wrote a Python program, saved it to a file, and executed it like a boss! Don’t celebrate too hard, though. You don’t want to develop Python software using Notepad or other simple text editors. What you really want is a Python IDE: an Integrated Development Environment. Sounds scary, but it’s not!

Get certified with our courses

Our premium courses offer a superior user experience with small, easy-to-digest lessons, progress tracking, quizzes to test your knowledge, and practice sessions. Each course will earn you a downloadable course certificate.

Learn more

This article is part of my Python tutorial. You can head over to the start of the tutorial here. You can navigate this tutorial using the buttons at the top and bottom of the articles. To get an overview of all articles in the tutorial, please use the fold-out menu at the top.

If you liked this article, you might also like to read the following articles:

Leave a Comment Cancel reply

You must be logged in to post a comment.

You are browsing the free Python tutorial. Make sure to check out my full Python courses as well.

Subscribe to my newsletter for Python news, tips, and tricks!

Источник