#! /usr/bin/env python
# -*- coding: utf-8 -*-
#
# Here we provide the necessary imports.
# The basic GUI widgets are located in QtGui module. 
import sys
from PyQt4.QtGui import *
 
# Every PyQt4 application must create an application object.
# The application object is located in the QtGui module.
a = QApplication(sys.argv)
 
# The QWidget widget is the base class of all user interface objects in PyQt4.
# We provide the default constructor for QWidget. The default constructor has no parent.
# A widget with no parent is called a window. 
w = QWidget()
 
w.resize(320, 240)  # The resize() method resizes the widget.
w.setWindowTitle("Hello, World!")  # Here we set the title for our window.
w.show()  # The show() method displays the widget on the screen.
 
sys.exit(a.exec_())  # Finally, we enter the mainloop of the application.

import gtk
 
def create_window():
    window = gtk.Window()
    window.set_default_size(200, 200)
    window.connect('destroy', gtk.main_quit)
 
    label = gtk.Label('Hello World')
    window.add(label)
 
    label.show()
    window.show()
 
create_window()
gtk.main()