simple IPython example raises exception on sys.exit()

Question

I\'m doing some very simple PySide (and PyQt) tutorials in IPython. One tutorial just creates a window with some sliders to demonstrate slots and signals.

When I clo

Answer 1

Check if already an instance of QApplication is present or not as the error occurs when an instance is already running and you are trying to create a new one.

if not QtWidgets.QApplication.instance():
    app = QtWidgets.QApplication(sys.argv)
else:
    app = QtWidgets.QApplication.instance()