Hello World, in Python3 and Qt5

helloworld_pyqt5.py

#!/usr/bin/env python3

"""
helloworld.py
Python3 and Qt5 
"""
 
from PyQt5 import QtWidgets


def main():
    app = QtWidgets.QApplication([])
    window = QtWidgets.QMainWindow()
    label = QtWidgets.QLabel('\tHello World!')
    window.setCentralWidget(label)
    window.show()
    app.exec_()


if __name__ == '__main__':
    main()

Thanks a lot! Also just a side note: in Python 3, exec is not a keyword any more, so with Python 3 and PyQt 5, you may now also write app.exec() rather than app.exec_()