Delphi is a powerful platform used by developers worldwide, to make stunning visual applications. Python, on the other hand is a powerful, general purpose object oriented language. Did you ever wonder if the power of both could ever be combined? Presenting to you, Python4Delphi! This set of free components works by wrapping up the Python DLL into Delphi and C++Builder thus enabling its users to view GUI for their Python scripts with ease. In this tutorial, we will show you just how easy it is to set up your P4D project and start building!
Prerequisites: Before we begin working, it is essential we Download the latest version of Python for your platform. You can find the installation instructions for Python4Delphi at this link. Alternatively, you can follow the easy instructions found in this video Getting started with Python4Delphi.
To get started with our Python Script to GUI journey, our first step would be to create a VCL application. Luckily for us, this has already been done for us by the people at Delphi! All we need to do in order to get started is download the Demo1 project from the P4D GitHub repository here. And run the application. Once you run the application, you will see a new window popping up on your screen. The new window titled “Demo of Python” will have two different Memos. The lower Memo is where our Python Script, for example print( “Hello World”) goes. The top Memo is where the GUI is displayed for our script.
If you would like to know more about how you can create an application of your own that is different from the VCL application provided to you in project Demo1, you can start by learning more about the implementation details here.
The Python Code:
This particular segment will explain the Python code that we will write to demonstrate how our Demo1 VCL application works. Since our focus in this tutorial is the explanation of basic string operators, let’s take a look at at some relevant code!
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# Creating some variables string1 = "Hello" string2 = "World!" #Concatenating Strings print(string1 + ' ' +string2) |
In the code above, we will be using the “+” operator to concatenate two different strings. This operator returns a singular string that can either be saved in a variable or it can be printed out.
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#Equating Strings string3 = string1 + string2 string4 = string3 print("String 3 : ", string3) print("String 4 : ", string4) |
This particular code works by creating a new string and setting its contents equal to another string. As you might observe in the first line, we have string3 which is equal to the concatenation of string1 and string2. Whereas string4 is a copy of string3. Let’s print them both out to double check if the results are identical or not.
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#String Indexing print(string3[0], string3[-1]) #String Slicing print(string4[0:5]) |
String Indexing allows you to pick out a single character from a string. This can be accomplished by writing down the name of your string variable followed by square brackets “[ ]” the indexing range starts from 0, and extends to the length of the string minus 1. Any number within this range will result in the printing of the element present at that index.
In string slicing however, we input a range of indexes instead of a single index. The starting number and ending number are separated by a colon ” : ” It should be noted that when using string slicing, the starting number will be included in the range whereas the ending number will not. Mathematically, we can represent it as (start, end].
Now let’s run the above code in our VCL application and see what results we can get.
Check out some more cool tutorials on Python4Delphi over here.
