first app using pyqt5
from PyQt5.QtWidgets import QApplication, QWidget
# Only needed for access to command line arguments
import sys
# You need one (and only one) QApplication instance per application.
# Pass in sys.argv to allow command line arguments for your app.
# If you know you won't use command line arguments QApplication([]) works too.
app = QApplication(sys.argv)
# Create a Qt widget, which will be our window.
window = QWidget()
window.show() # IMPORTANT!!!!! Windows are hidden by default.
# Start the event loop.
app.exec()
# Your application won't reach here until you exit and the event
# loop has stopped.