Python Design Patterns 简明教程

import json

class Person(object):
   def __init__(self, first_name = None, last_name = None):
      self.first_name = first_name
      self.last_name = last_name
   #returns Person name, ex: John Doe
   def name(self):
      return ("%s %s" % (self.first_name,self.last_name))

   @classmethod
   #returns all people inside db.txt as list of Person objects
   def getAll(self):
      database = open('db.txt', 'r')
      result = []
      json_list = json.loads(database.read())
      for item in json_list:
         item = json.loads(item)
         person = Person(item['first_name'], item['last_name'])
         result.append(person)
      return result

from model import Person
def showAllView(list):
   print 'In our db we have %i users. Here they are:' % len(list)
   for item in list:
      print item.name()
def startView():
   print 'MVC - the simplest example'
   print 'Do you want to see everyone in my db?[y/n]'
def endView():
   print 'Goodbye!'

from model import Person
import view

def showAll():
   #gets list of all Person objects
   people_in_db = Person.getAll()
   #calls view
   return view.showAllView(people_in_db)

def start():
   view.startView()
   input = raw_input()
   if input == 'y':
      return showAll()
   else:
      return view.endView()

if __name__ == "__main__":
   #running controller function
   start()

class Singleton:
   __instance = None
   @staticmethod
   def getInstance():
      """ Static access method. """
      if Singleton.__instance == None:
         Singleton()
      return Singleton.__instance
   def __init__(self):
      """ Virtually private constructor. """
      if Singleton.__instance != None:
         raise Exception("This class is a singleton!")
      else:
         Singleton.__instance = self
s = Singleton()
print s

s = Singleton.getInstance()
print s

s = Singleton.getInstance()
print s

class Button(object):
   html = ""
   def get_html(self):
      return self.html

class Image(Button):
   html = "<img></img>"

class Input(Button):
   html = "<input></input>"

class Flash(Button):
   html = "<obj></obj>"

class ButtonFactory():
   def create_button(self, typ):
      targetclass = typ.capitalize()
      return globals()[targetclass]()

button_obj = ButtonFactory()
button = ['image', 'input', 'flash']
for b in button:
   print button_obj.create_button(b).get_html()

class Director:
   __builder = None

   def setBuilder(self, builder):
      self.__builder = builder

   def getCar(self):
      car = Car()

      # First goes the body
      body = self.__builder.getBody()
      car.setBody(body)

      # Then engine
      engine = self.__builder.getEngine()
      car.setEngine(engine)

      # And four wheels
      i = 0
      while i < 4:
         wheel = self.__builder.getWheel()
			car.attachWheel(wheel)
         i += 1
      return car

# The whole product
class Car:
   def __init__(self):
      self.__wheels = list()
      self.__engine = None
      self.__body = None

   def setBody(self, body):
      self.__body = body

   def attachWheel(self, wheel):
      self.__wheels.append(wheel)

   def setEngine(self, engine):
      self.__engine = engine

   def specification(self):
      print "body: %s" % self.__body.shape
      print "engine horsepower: %d" % self.__engine.horsepower
      print "tire size: %d\'" % self.__wheels[0].size

class Builder:
      def getWheel(self): pass
      def getEngine(self): pass
      def getBody(self): pass

class JeepBuilder(Builder):

   def getWheel(self):
      wheel = Wheel()
      wheel.size = 22
      return wheel

   def getEngine(self):
      engine = Engine()
      engine.horsepower = 400
      return engine

   def getBody(self):
      body = Body()
      body.shape = "SUV"
      return body

# Car parts
class Wheel:
   size = None

class Engine:
   horsepower = None

class Body:
   shape = None

def main():
   jeepBuilder = JeepBuilder() # initializing the class

   director = Director()

   # Build Jeep
   print "Jeep"
   director.setBuilder(jeepBuilder)
   jeep = director.getCar()
   jeep.specification()
   print ""

if __name__ == "__main__":
   main()

import copy

class Prototype:

   _type = None
   _value = None

   def clone(self):
      pass

   def getType(self):
      return self._type

   def getValue(self):
      return self._value

class Type1(Prototype):

   def __init__(self, number):
      self._type = "Type1"
      self._value = number

   def clone(self):
      return copy.copy(self)

class Type2(Prototype):

   """ Concrete prototype. """

   def __init__(self, number):
      self._type = "Type2"
      self._value = number

   def clone(self):
      return copy.copy(self)

class ObjectFactory:

   """ Manages prototypes.
   Static factory, that encapsulates prototype
   initialization and then allows instatiation
   of the classes from these prototypes.
   """

   __type1Value1 = None
   __type1Value2 = None
   __type2Value1 = None
   __type2Value2 = None

   @staticmethod
   def initialize():
      ObjectFactory.__type1Value1 = Type1(1)
      ObjectFactory.__type1Value2 = Type1(2)
      ObjectFactory.__type2Value1 = Type2(1)
      ObjectFactory.__type2Value2 = Type2(2)

   @staticmethod
   def getType1Value1():
      return ObjectFactory.__type1Value1.clone()

   @staticmethod
   def getType1Value2():
      return ObjectFactory.__type1Value2.clone()

   @staticmethod
   def getType2Value1():
      return ObjectFactory.__type2Value1.clone()

   @staticmethod
   def getType2Value2():
      return ObjectFactory.__type2Value2.clone()

def main():
   ObjectFactory.initialize()

   instance = ObjectFactory.getType1Value1()
   print "%s: %s" % (instance.getType(), instance.getValue())

   instance = ObjectFactory.getType1Value2()
   print "%s: %s" % (instance.getType(), instance.getValue())

   instance = ObjectFactory.getType2Value1()
   print "%s: %s" % (instance.getType(), instance.getValue())

   instance = ObjectFactory.getType2Value2()
   print "%s: %s" % (instance.getType(), instance.getValue())

if __name__ == "__main__":
   main()

class _IgnitionSystem(object):

   @staticmethod
   def produce_spark():
      return True

class _Engine(object):

   def __init__(self):
      self.revs_per_minute = 0

   def turnon(self):
      self.revs_per_minute = 2000

   def turnoff(self):
      self.revs_per_minute = 0

class _FuelTank(object):

   def __init__(self, level=30):
      self._level = level

   @property
   def level(self):
      return self._level

   @level.setter
	def level(self, level):
      self._level = level

class _DashBoardLight(object):

   def __init__(self, is_on=False):
      self._is_on = is_on

   def __str__(self):
      return self.__class__.__name__

   @property
   def is_on(self):
      return self._is_on

   @is_on.setter
   def is_on(self, status):
      self._is_on = status

   def status_check(self):
      if self._is_on:
         print("{}: ON".format(str(self)))
      else:
         print("{}: OFF".format(str(self)))

class _HandBrakeLight(_DashBoardLight):
   pass

class _FogLampLight(_DashBoardLight):
   pass

class _Dashboard(object):

   def __init__(self):
      self.lights = {"handbreak": _HandBrakeLight(), "fog": _FogLampLight()}

   def show(self):
	   for light in self.lights.values():
      light.status_check()

# Facade
class Car(object):

   def __init__(self):
      self.ignition_system = _IgnitionSystem()
      self.engine = _Engine()
      self.fuel_tank = _FuelTank()
      self.dashboard = _Dashboard()

   @property
   def km_per_litre(self):
      return 17.0

   def consume_fuel(self, km):
      litres = min(self.fuel_tank.level, km / self.km_per_litre)
      self.fuel_tank.level -= litres

   def start(self):
      print("\nStarting...")
      self.dashboard.show()
      if self.ignition_system.produce_spark():
         self.engine.turnon()
      else:
         print("Can't start. Faulty ignition system")

   def has_enough_fuel(self, km, km_per_litre):
      litres_needed = km / km_per_litre
      if self.fuel_tank.level > litres_needed:
         return True
      else:
         return False

      def drive(self, km = 100):
         print("\n")
         if self.engine.revs_per_minute > 0:
            while self.has_enough_fuel(km, self.km_per_litre):
               self.consume_fuel(km)
               print("Drove {}km".format(km))
               print("{:.2f}l of fuel still left".format(self.fuel_tank.level))
         else:
            print("Can't drive. The Engine is turned off!")

         def park(self):
            print("\nParking...")
            self.dashboard.lights["handbreak"].is_on = True
            self.dashboard.show()
            self.engine.turnoff()

         def switch_fog_lights(self, status):
            print("\nSwitching {} fog lights...".format(status))
            boolean = True if status == "ON" else False
            self.dashboard.lights["fog"].is_on = boolean
            self.dashboard.show()

         def fill_up_tank(self):
            print("\nFuel tank filled up!")
            self.fuel_tank.level = 100

# the main function is the Client
def main():
   car = Car()
   car.start()
   car.drive()
   car.switch_fog_lights("ON")
   car.switch_fog_lights("OFF")
	car.park()
   car.fill_up_tank()
   car.drive()
   car.start()
   car.drive()

if __name__ == "__main__":
   main()

def demo(a,b,c):
   print 'a:',a
   print 'b:',b
   print 'c:',c

class Command:
   def __init__(self, cmd, *args):
      self._cmd=cmd
      self._args=args

   def __call__(self, *args):
      return apply(self._cmd, self._args+args)
cmd = Command(dir,__builtins__)
print cmd()

cmd = Command(demo,1,2)
cmd(3)

class EuropeanSocketInterface:
   def voltage(self): pass

   def live(self): pass
   def neutral(self): pass
   def earth(self): pass

# Adaptee
class Socket(EuropeanSocketInterface):
   def voltage(self):
      return 230

	def live(self):
      return 1

   def neutral(self):
      return -1

   def earth(self):
      return 0

# Target interface
class USASocketInterface:
   def voltage(self): pass
   def live(self): pass
   def neutral(self): pass

# The Adapter
class Adapter(USASocketInterface):
   __socket = None
   def __init__(self, socket):
      self.__socket = socket

   def voltage(self):
      return 110

   def live(self):
      return self.__socket.live()

   def neutral(self):
      return self.__socket.neutral()

# Client
class ElectricKettle:
   __power = None

   def __init__(self, power):
	   self.__power = power

   def boil(self):
      if self.__power.voltage() > 110:
         print "Kettle on fire!"
      else:
         if self.__power.live() == 1 and \
            self.__power.neutral() == -1:
            print "Coffee time!"
         else:
            print "No power."

def main():
   # Plug in
   socket = Socket()
   adapter = Adapter(socket)
   kettle = ElectricKettle(adapter)

   # Make coffee
   kettle.boil()

   return 0

if __name__ == "__main__":
   main()

import six
from abc import ABCMeta

@six.add_metaclass(ABCMeta)
class Abstract_Coffee(object):

   def get_cost(self):
      pass

   def get_ingredients(self):
      pass

   def get_tax(self):
      return 0.1*self.get_cost()

class Concrete_Coffee(Abstract_Coffee):

   def get_cost(self):
      return 1.00

   def get_ingredients(self):
      return 'coffee'

@six.add_metaclass(ABCMeta)
class Abstract_Coffee_Decorator(Abstract_Coffee):

   def __init__(self,decorated_coffee):
      self.decorated_coffee = decorated_coffee

   def get_cost(self):
      return self.decorated_coffee.get_cost()

   def get_ingredients(self):
      return self.decorated_coffee.get_ingredients()

class Sugar(Abstract_Coffee_Decorator):

   def __init__(self,decorated_coffee):
      Abstract_Coffee_Decorator.__init__(self,decorated_coffee)

   def get_cost(self):
      return self.decorated_coffee.get_cost()

   def get_ingredients(self):
	   return self.decorated_coffee.get_ingredients() + ', sugar'

class Milk(Abstract_Coffee_Decorator):

   def __init__(self,decorated_coffee):
      Abstract_Coffee_Decorator.__init__(self,decorated_coffee)

   def get_cost(self):
      return self.decorated_coffee.get_cost() + 0.25

   def get_ingredients(self):
      return self.decorated_coffee.get_ingredients() + ', milk'

class Vanilla(Abstract_Coffee_Decorator):

   def __init__(self,decorated_coffee):
      Abstract_Coffee_Decorator.__init__(self,decorated_coffee)

   def get_cost(self):
      return self.decorated_coffee.get_cost() + 0.75

   def get_ingredients(self):
      return self.decorated_coffee.get_ingredients() + ', vanilla'

import coffeeshop

myCoffee = coffeeshop.Concrete_Coffee()
print('Ingredients: '+myCoffee.get_ingredients()+
   '; Cost: '+str(myCoffee.get_cost())+'; sales tax = '+str(myCoffee.get_tax()))

myCoffee = coffeeshop.Milk(myCoffee)
print('Ingredients: '+myCoffee.get_ingredients()+
   '; Cost: '+str(myCoffee.get_cost())+'; sales tax = '+str(myCoffee.get_tax()))

myCoffee = coffeeshop.Vanilla(myCoffee)
print('Ingredients: '+myCoffee.get_ingredients()+
   '; Cost: '+str(myCoffee.get_cost())+'; sales tax = '+str(myCoffee.get_tax()))

myCoffee = coffeeshop.Sugar(myCoffee)
print('Ingredients: '+myCoffee.get_ingredients()+
   '; Cost: '+str(myCoffee.get_cost())+'; sales tax = '+str(myCoffee.get_tax()))

class Image:
   def __init__( self, filename ):
      self._filename = filename

   def load_image_from_disk( self ):
      print("loading " + self._filename )

   def display_image( self ):
      print("display " + self._filename)

class Proxy:
   def __init__( self, subject ):
      self._subject = subject
      self._proxystate = None

class ProxyImage( Proxy ):
   def display_image( self ):
      if self._proxystate == None:
         self._subject.load_image_from_disk()
         self._proxystate = 1
      print("display " + self._subject._filename )

proxy_image1 = ProxyImage ( Image("HiRes_10Mb_Photo1") )
proxy_image2 = ProxyImage ( Image("HiRes_10Mb_Photo2") )

proxy_image1.display_image() # loading necessary
proxy_image1.display_image() # loading unnecessary
proxy_image2.display_image() # loading necessary
proxy_image2.display_image() # loading unnecessary
proxy_image1.display_image() # loading unnecessary

class ReportFormat(object):
   PDF = 0
   TEXT = 1
class Report(object):
   def __init__(self, format_):
      self.title = 'Monthly report'
      self.text = ['Things are going', 'really, really well.']
      self.format_ = format_

class Handler(object):
   def __init__(self):
      self.nextHandler = None

   def handle(self, request):
      self.nextHandler.handle(request)

class PDFHandler(Handler):

   def handle(self, request):
      if request.format_ == ReportFormat.PDF:
         self.output_report(request.title, request.text)
      else:
         super(PDFHandler, self).handle(request)

   def output_report(self, title, text):
      print '<html>'
      print ' <head>'
      print ' <title>%s</title>' % title
      print ' </head>'
      print ' <body>'
      for line in text:
         print ' <p>%s' % line
      print ' </body>'
      print '</html>'

class TextHandler(Handler):

   def handle(self, request):
      if request.format_ == ReportFormat.TEXT:
         self.output_report(request.title, request.text)
      else:
         super(TextHandler, self).handle(request)

   def output_report(self, title, text):
      print 5*'*' + title + 5*'*'
      for line in text:
         print line

class ErrorHandler(Handler):
   def handle(self, request):
      print "Invalid request"

if __name__ == '__main__':
   report = Report(ReportFormat.TEXT)
   pdf_handler = PDFHandler()
   text_handler = TextHandler()

   pdf_handler.nextHandler = text_handler
   text_handler.nextHandler = ErrorHandler()
	pdf_handler.handle(report)

import threading
import time
import pdb

class Downloader(threading.Thread):

   def run(self):
      print 'downloading'
      for i in range(1,5):
         self.i = i
         time.sleep(2)
			print 'unfunf'
         return 'hello world'

class Worker(threading.Thread):
   def run(self):
      for i in range(1,5):
         print 'worker running: %i (%i)' % (i, t.i)
         time.sleep(1)
         t.join()

         print 'done'

t = Downloader()
t.start()

time.sleep(1)

t1 = Worker()
t1.start()

t2 = Worker()
t2.start()

t3 = Worker()
t3.start()

class ComputerState(object):

   name = "state"
   allowed = []

   def switch(self, state):
      """ Switch to new state """
      if state.name in self.allowed:
         print 'Current:',self,' => switched to new state',state.name
         self.__class__ = state
      else:
         print 'Current:',self,' => switching to',state.name,'not possible.'

   def __str__(self):
      return self.name

class Off(ComputerState):
   name = "off"
   allowed = ['on']

class On(ComputerState):
   """ State of being powered on and working """
   name = "on"
   allowed = ['off','suspend','hibernate']

class Suspend(ComputerState):
   """ State of being in suspended mode after switched on """
   name = "suspend"
   allowed = ['on']

class Hibernate(ComputerState):
   """ State of being in hibernation after powered on """
   name = "hibernate"
   allowed = ['on']

class Computer(object):
   """ A class representing a computer """

   def __init__(self, model='HP'):
      self.model = model
      # State of the computer - default is off.
      self.state = Off()

   def change(self, state):
      """ Change state """
      self.state.switch(state)

if __name__ == "__main__":
   comp = Computer()
   comp.change(On)
   comp.change(Off)
   comp.change(On)
   comp.change(Suspend)
   comp.change(Hibernate)
   comp.change(On)
   comp.change(Off)

import types

class StrategyExample:
   def __init__(self, func = None):
      self.name = 'Strategy Example 0'
      if func is not None:
         self.execute = types.MethodType(func, self)

   def execute(self):
      print(self.name)

def execute_replacement1(self):
   print(self.name + 'from execute 1')

def execute_replacement2(self):
   print(self.name + 'from execute 2')

if __name__ == '__main__':
   strat0 = StrategyExample()
   strat1 = StrategyExample(execute_replacement1)
   strat1.name = 'Strategy Example 1'
   strat2 = StrategyExample(execute_replacement2)
   strat2.name = 'Strategy Example 2'
   strat0.execute()
   strat1.execute()
   strat2.execute()

class ComplexGenetics(object):
   def __init__(self):
      pass

   def genes(self, gene_code):
      return "ComplexPatter[%s]TooHugeinSize" % (gene_code)
class Families(object):
   family = {}

   def __new__(cls, name, family_id):
      try:
         id = cls.family[family_id]
      except KeyError:
         id = object.__new__(cls)
         cls.family[family_id] = id
      return id

   def set_genetic_info(self, genetic_info):
      cg = ComplexGenetics()
      self.genetic_info = cg.genes(genetic_info)

   def get_genetic_info(self):
      return (self.genetic_info)

def test():
   data = (('a', 1, 'ATAG'), ('a', 2, 'AAGT'), ('b', 1, 'ATAG'))
   family_objects = []
   for i in data:
      obj = Families(i[0], i[1])
      obj.set_genetic_info(i[2])
      family_objects.append(obj)

   for i in family_objects:
      print "id = " + str(id(i))
      print i.get_genetic_info()
   print "similar id's says that they are same objects "

if __name__ == '__main__':
   test()

class Window:
   __toolkit = ""
   __purpose = ""

   def __init__(self, toolkit, purpose):
      self.__toolkit = toolkit
      self.__purpose = purpose

   def getToolkit(self):
      return self.__toolkit

   def getType(self):
      return self.__purpose

class GtkToolboxWindow(Window):
   def __init__(self):
      Window.__init__(self, "Gtk", "ToolboxWindow")

class GtkLayersWindow(Window):
   def __init__(self):
      Window.__init__(self, "Gtk", "LayersWindow")

class GtkMainWindow(Window):
   def __init__(self):
      Window.__init__(self, "Gtk", "MainWindow")

class QtToolboxWindow(Window):
   def __init__(self):
      Window.__init__(self, "Qt", "ToolboxWindow")

class QtLayersWindow(Window):
   def __init__(self):
      Window.__init__(self, "Qt", "LayersWindow")

class QtMainWindow(Window):
   def __init__(self):
      Window.__init__(self, "Qt", "MainWindow")

# Abstract factory class
class UIFactory:
   def getToolboxWindow(self): pass
   def getLayersWindow(self): pass
   def getMainWindow(self): pass

class GtkUIFactory(UIFactory):
   def getToolboxWindow(self):
      return GtkToolboxWindow()
   def getLayersWindow(self):
      return GtkLayersWindow()
   def getMainWindow(self):
      return GtkMainWindow()

class QtUIFactory(UIFactory):
   def getToolboxWindow(self):
      return QtToolboxWindow()
   def getLayersWindow(self):
      return QtLayersWindow()
   def getMainWindow(self):
      return QtMainWindow()

if __name__ == "__main__":
   gnome = True
   kde = not gnome

   if gnome:
      ui = GtkUIFactory()
   elif kde:
      ui = QtUIFactory()

   toolbox = ui.getToolboxWindow()
   layers = ui.getLayersWindow()
   main = ui.getMainWindow()

   print "%s:%s" % (toolbox.getToolkit(), toolbox.getType())
   print "%s:%s" % (layers.getToolkit(), layers.getType())
   print "%s:%s" % (main.getToolkit(), main.getType())

class Parrot:
   # class attribute
   species = "bird"

   # instance attribute
   def __init__(self, name, age):
      self.name = name
      self.age = age

# instantiate the Parrot class
blu = Parrot("Blu", 10)
woo = Parrot("Woo", 15)

# access the class attributes
print("Blu is a {}".format(blu.__class__.species))
print("Woo is also a {}".format(woo.__class__.species))

# access the instance attributes
print("{} is {} years old".format( blu.name, blu.age))
print("{} is {} years old".format( woo.name, woo.age))

class Robot:
   population = 0

   def __init__(self, name):
      self.name = name
      print("(Initializing {})".format(self.name))
      Robot.population += 1

   def die(self):
      print("{} is being destroyed!".format(self.name))
      Robot.population -= 1
      if Robot.population == 0:
         print("{} was the last one.".format(self.name))
      else:
         print("There are still {:d} robots working.".format(
            Robot.population))

   def say_hi(self):
      print("Greetings, my masters call me {}.".format(self.name))

   @classmethod
   def how_many(cls):
      print("We have {:d} robots.".format(cls.population))
droid1 = Robot("R2-D2")
droid1.say_hi()
Robot.how_many()

droid2 = Robot("C-3PO")
droid2.say_hi()
Robot.how_many()

print("\nRobots can do some work here.\n")

print("Robots have finished their work. So let's destroy them.")
droid1.die()
droid2.die()

Robot.how_many()

import time

def fib():
   a, b = 0, 1
   while True:
      yield b
      a, b = b, a + b

g = fib()

try:
   for e in g:
      print(e)
      time.sleep(1)

except KeyboardInterrupt:
   print("Calculation stopped")

# Create a new dictionary
d = dict() # or d = {}

# Add a key - value pairs to dictionary
d['xyz'] = 123
d['abc'] = 345

# print the whole dictionary
print(d)

# print only the keys
print(d.keys())

# print only values
print(d.values())

# iterate over dictionary
for i in d :
   print("%s %d" %(i, d[i]))

# another method of iteration
for index, value in enumerate(d):
   print (index, value , d[value])

# check if key exist 23. Python Data Structure –print('xyz' in d)

# delete the key-value pair
del d['xyz']

# check again
print("xyz" in d)

List_name = [ elements ];

my_list = ['p','r','o','b','e']
# Output: p
print(my_list[0])

# Output: o
print(my_list[2])

# Output: e
print(my_list[4])

# Error! Only integer can be used for indexing
# my_list[4.0]

# Nested List
n_list = ["Happy", [2,0,1,5]]

# Nested indexing

# Output: a
print(n_list[0][1])

# Output: 5
print(n_list[1][3])

# Set in Python

# Creating two sets
set1 = set()
set2 = set()

# Adding elements to set1
for i in range(1, 6):
   set1.add(i)

# Adding elements to set2
for i in range(3, 8):
   set2.add(i)

print("Set1 = ", set1)
print("Set2 = ", set2)
print("\n")

# Union of set1 and set2
set3 = set1 | set2# set1.union(set2)
print("Union of Set1 & Set2: Set3 = ", set3)

# Intersection of set1 and set2
set4 = set1 & set2# set1.intersection(set2)
print("Intersection of Set1 & Set2: Set4 = ", set4)
print("\n")

# Checking relation between set3 and set4
if set3 > set4: # set3.issuperset(set4)
   print("Set3 is superset of Set4")
elif set3 < set4: # set3.issubset(set4)
   print("Set3 is subset of Set4")
else : # set3 == set4
   print("Set3 is same as Set4")

# displaying relation between set4 and set3
if set4 < set3: # set4.issubset(set3)
   print("Set4 is subset of Set3")
   print("\n")

# difference between set3 and set4
set5 = set3 - set4
print("Elements in Set3 and not in Set4: Set5 = ", set5)
print("\n")

# checkv if set4 and set5 are disjoint sets
if set4.isdisjoint(set5):
   print("Set4 and Set5 have nothing in common\n")

# Removing all the values of set5
set5.clear()

print("After applying clear on sets Set5: ")
print("Set5 = ", set5)

import Queue

q = Queue.Queue()

#put items at the end of the queue
for x in range(4):
   q.put("item-" + str(x))

#remove items from the head of the queue
while not q.empty():
   print q.get()

import Queue

q = Queue.LifoQueue()

#add items at the head of the queue
for x in range(4):
   q.put("item-" + str(x))

#remove items from the head of the queue
while not q.empty():
   print q.get()