Vissles recently sent me their new LP85 keyboard to review, and I've spent a few weeks giving the keyboard a go. I have already reviewed the V84 mechanical keyboard from Vissles just a few months ago and that keyboard has been my daily driver ever since. I was therefore very interested in testing out this new product. The LP85 is a low profile keyboard with optical switches that come in a sleek aluminium chassis. Instead of the usual mechanical switches that make a physical connection, optical switches break a beam of infrared light to activate the key press. As there is no physical switch being clicked this means that optical switches last longer than mechanical ones.
A calculator is a great application to create when learning how to code as it contains many of the things that most GUI applications will have, including behind the scenes processing of results. Things like triggering events from buttons, accepting user input, and producing output from that input are pretty standard in GUI applications and a calculator has all of them. There are also a couple of features in Python that makes building the application pretty simple. In this article I will look at designing and building the interface using Tkinter, followed by creating the code to process the entered sums into a result.
The Canvas element that comes with Tkinter is quite versatile. Out of the box you can draw simple basic shapes like squares and circles, but also lines and more complex shapes made up of points. You can even add text and images to the canvas.
This article will go through all of the different types of items you can draw using the Tkinter Canvas object.
Before getting into that, it's important to understand how coordinates are used on a canvas object. Drawing items on a canvas requires the use of an x and y coordinate to pinpoint where the item is to be drawn. All points are relative to the top left hand corner, so a coordinate of 0,0 would be right in the top left corner.
When creating Drupal modules I like to keep the hard coded components to a minimum. This helps when changing parts of the module in the future as hard coded links and other elements will require manual intervention and slow down maintenance. Sometimes, though, this isn't an option as you just need to have a few routes in your *.routing.yml file that point to controllers or forms within your module.
I had a situation today where I was looking to load all of the routes that are contained in a module. I could then construct a page of links that would handily point to different parts of the module or feed those links into a sitemap. This meant that I wouldn't need to hard code this list into a controller, I just needed to load all the routes and print that list out instead. Especially handy if I ever added or removed a route as that would mean that list would update without me having to do it manually.
I recently saw a design of a physical clock that inspired me to go about creating one using Python and Tkinter. The clock was essentially a wall of letters with lights behind that light up depending on what time it is. Without the lights the clock looks like a jumble of letters, it is only when the light is on that the relevant time is displayed.
The original clock was of a proprietary design so I set about creating one that was based more on an open source clock design that I found. That clock design I found didn't display the AM or PM of the time, so I ended up tweaking that design a little anyway.
Changing time into different formats is quite a common thing to do in programming. I have seen examples that change times into Roman numerals and other formats, but I realised I hadn't seen any code that changed the current time into a sentence. This means converting a numeric time value into a sentence that can be read. For example, the time 9:05 can be read as "it is five past nine", or if the time is 9:00 then it would read "it is nine o'clock". At it turns out, there are only a few rules that govern doing this.
SOLID is a set of object oriented design principles aimed at making code more maintainable and flexible. They were coined by Robert "Uncle Bob" Martin in the year 2000 in his paper Design Principles and Design Patterns. The SOLID principles apply to any object oriented language, but I'm going to concentrate on what they mean in a Python application in this post.
I originally wrote about SOLID principles with PHP as the basis of the article, but as the lessons here can be easily applied to any object oriented language I thought that I would re-write it with Python in mind. If you are familiar with only PHP or Python then this will be a good learning resource on learning the other side.
I have been learning Python recently, and whilst I'm familiar with PHP and other C-like languages, Python has been a bit of a challenge to get used to due to the different syntax. This is especially the case with objects as although Python is object oriented there are a couple of gotchas when creating custom objects. This article sets out how to use classes and objects, but I will assume that you have a basic understanding of object oriented programming in other languages.
The Python Tkinter module has a lot of widgets built in that provide different parts of the graphical user interface. Everything from labels to buttons are all widgets and they extend from the base Widget class. Some Widgets are easy to put together, but others require a little bit of configuration to get working. This article will show each Tkinter widget available and how to add each one to an application. There are two sorts of Widgets available. Simple widgets exist in their own right, but some widgets are made to contain other widgets.
Strings and arrays can be manipulated in a number of ways in python. Splitting a string or an array into sections can be done using the section slicing that is built into the core python syntax and uses the colon (:) symbol.
Generating a simple array in python is straightforward, the following creates an array of 9 elements.
an_array = [1,2,3,4,5,6,7,8,9]
To grab a particular element of the array you can use the simplest section slicing syntax. The number in the square brackets represents the position of the item to be returned. Remember that the counting starts at 0, so using 1 will return the item from the "second" position.