This example shows how you can create a Hello World app using PyQt. It uses a QLabel to display a simple window:
from PyQt5.QtWidgets import *
app = QApplication([])
label = QLabel('Hello World!')
label.show()
app.exec_()
For instructions how you can run this code, please see the top-level README.
The code works as follows: First, we import the necessary PyQt classes via the statement:
from PyQt5.QtWidgets import *
Next, we create a QApplication. This is required in every PyQt app. In a sense, it initializes PyQt:
app = QApplication([])
Then, we create the label with the text we want:
label = QLabel('Hello World!')
By calling .show() on a widget, we can spawn a window that displays it:
label.show()
Finally, we hand control over to Qt:
app.exec_()
This too is required in every Qt application. It gives Qt a chance to run and process user input, such as for instance when the user clicks the "Window close" button.
And that's it! Congratulations on your first PyQt app :-)