# 迭代器、装饰器、生成器

# 迭代器

li = [1, 3, 'he', '&']

n = iter(li)

print(n.__next__())

import os, sys

# 生成器

def func():

    for i in xrange(10):

        yield (i)

        print(i)

 # 装饰器

 #使用装饰函数在函数执行前和执行后分别附加额外功能

 '''示例2: 替换函数(装饰)

 装饰函数的参数是被装饰的函数对象，返回原函数对象

 装饰的实质语句: myfunc = deco(myfunc)'''

 def deco(func):

     print("before myfunc() called.")

     func()

     print("  after myfunc() called.")

     return func

 def myfunc():

     print(" myfunc() called.")

 myfunc = deco(myfunc)

 myfunc()

 myfunc()

 #使用语法糖@来装饰函数

 '''示例3: 使用语法糖@来装饰函数，相当于“myfunc = deco(myfunc)”

 但发现新函数只在第一次被调用，且原函数多调用了一次'''

 def deco(func):

     print("before myfunc() called.")

     func()

     print("  after myfunc() called.")

     return func

 @deco

 def myfunc():

     print(" myfunc() called.")

 myfunc()

 myfunc()

 #用内嵌包装函数来确保每次新函数都被调用

 def deco(func):

     def _deco():

         print("before myfunc() called.")

         func()

         print("  after myfunc() called.")

         # 不需要返回func，实际上应返回原函数的返回值

     return _deco

 @deco

 def myfunc():

     print(" myfunc() called.")

     return 'ok'

 myfunc()

 myfunc()

 #对带参数的函数进行装饰

 def deco(func):

     def _deco(a, b):

         print("before myfunc() called.")

         ret = func(a, b)

         print("  after myfunc() called. result: %s" % ret)

         return ret

     return _deco

 @deco

 def myfunc(a, b):

     print(" myfunc(%s,%s) called." % (a, b))

     return a + b

 myfunc(1, 2)

 myfunc(3, 4)

 #对参数数量不确定的函数进行装饰

 '''示例6: 对参数数量不确定的函数进行装饰，

 参数用(*args, **kwargs)，自动适应变参和命名参数'''

 def deco(func):

     def _deco(*args, **kwargs):

         print("before %s called." % func.__name__)

         ret = func(*args, **kwargs)

         print("  after %s called. result: %s" % (func.__name__, ret))

         return ret

     return _deco

 @deco

 def myfunc(a, b):

     print(" myfunc(%s,%s) called." % (a, b))

     return a+b

 @deco

 def myfunc2(a, b, c):

     print(" myfunc2(%s,%s,%s) called." % (a, b, c))

     return a+b+c

 myfunc(1, 2)

 myfunc(3, 4)

 myfunc2(1, 2, 3)

 myfunc2(3, 4, 5)

 #让装饰器带参数

 def deco(arg):

     def _deco(func):

         def __deco():

             print("before %s called [%s]." % (func.__name__, arg))

             func()

             print("  after %s called [%s]." % (func.__name__, arg))

         return __deco

     return _deco

 @deco("mymodule")

 def myfunc():

     print(" myfunc() called.")

 @deco("module2")

 def myfunc2():

     print(" myfunc2() called.")

 myfunc()

 myfunc2()

 #让装饰器带 类 参数

 '''示例8: 装饰器带类参数'''

 class locker:

     def __init__(self):

         print("locker.__init__() should be not called.")

     @staticmethod

     def acquire():

         print("locker.acquire() called.（这是静态方法）")

     @staticmethod

     def release():

         print("  locker.release() called.（不需要对象实例）")

 def deco(cls):

     '''cls 必须实现acquire和release静态方法'''

     def _deco(func):

         def __deco():

             print("before %s called [%s]." % (func.__name__, cls))

             cls.acquire()

             try:

                 return func()

             finally:

                 cls.release()

         return __deco

     return _deco

 @deco(locker)

 def myfunc():

     print(" myfunc() called.")

 myfunc()

 myfunc()

 #装饰器带类参数，并分拆公共类到其他py文件中，同时演示了对一个函数应用多个装饰器

 '''mylocker.py: 公共类 for 示例9.py'''

 class mylocker:

     def __init__(self):

         print("mylocker.__init__() called.")

     @staticmethod

     def acquire():

         print("mylocker.acquire() called.")

     @staticmethod

     def unlock():

         print("  mylocker.unlock() called.")

 class lockerex(mylocker):

     @staticmethod

     def acquire():

         print("lockerex.acquire() called.")

     @staticmethod

     def unlock():

         print("  lockerex.unlock() called.")

 def lockhelper(cls):

     '''cls 必须实现acquire和release静态方法'''

     def _deco(func):

         def __deco(*args, **kwargs):

             print("before %s called." % func.__name__)

             cls.acquire()

             try:

                 return func(*args, **kwargs)

             finally:

                 cls.unlock()

         return __deco

     return _deco

 '''示例9: 装饰器带类参数，并分拆公共类到其他py文件中

 同时演示了对一个函数应用多个装饰器'''

 from mylocker import *

 class example:

     @lockhelper(mylocker)

     def myfunc(self):

         print(" myfunc() called.")

     @lockhelper(mylocker)

     @lockhelper(lockerex)

     def myfunc2(self, a, b):

         print(" myfunc2() called.")

         return a + b

 if __name__=="__main__":

     a = example()

     a.myfunc()

     print(a.myfunc())

     print(a.myfunc2(1, 2))

     print(a.myfunc2(3, 4))

 # 递归

 #斐波那契数列

 def func(arg1, arg2, stop):

     if arg1 == 0:

         print(arg1, arg2)

     arg3 = arg1 + arg2

     print(arg3)

     if arg3 < stop:

         func(arg2, arg3, stop)

 func(0, 1, 60)

 #算法基础之二分查找

 def data_search(data,find_d):

     mid=int(len(data)/2)

     if len(data)>=1:

         if data[mid]>find_d:

             print("data in thie left of [%s]"%data[mid])

             data_search(data[:mid],find_d)

         elif data[mid]<find_d:

             print("data in right of [%s]"%data[mid])

             data_search(data[mid:],find_d)

         else:

             print("found find_d",data[mid])

     else:

         print("cannot find`````")

 if __name__=="__main__":

     data=list(range(1,60000000))

     data_search(data,99)

 #二维数组旋转

 data=[[col for col in range(4)]for row in range(4)]

 print(data)

 for rindex,row in enumerate(data):

     print(rindex,row)

     for cindex in range(rindex,len(row)):

         tmp=data[cindex][rindex]

         data[cindex][rindex]=row[cindex]

         data[rindex][cindex]=tmp

     print('-------------------------')

     for r in data:print(r)