Python Function Note

Python Function Note

 #汉诺塔问题Python实现
 def my_move(n, a, b, c):
   if n == 1:
     print(a + ' --> ' + c)
   else:
     my_move(n-1, a, c, b)#将前n-1个盘子从a放到b
     my_move(1, a, b, c)#将最下面的盘子从a放到c
     my_move(n-1, b, a, c)#将b上的n-1个盘子放到c上
   return

 #杨辉三角Python实现
 def my_triangles(max):
   i = 1
   now = [1]
   while i <= max:
     yield now#保存当前list
     now = [1] + [now[n]+now[n+1] for n in range(len(now)-1)] + [1]#构建下层list
     i+=1
   print('done')

 #实现将‘123.456’转换成123.456，即函数float的实现
 def my_float(s):
   def my_front(x, y):
     return x*10+y
   def my_behind(x, y):
     return x*0.1+y

   front = s.split('.')[0]
   behind = s.split('.')[1]
   return reduce(my_front, map(int, front)) + 0.1*reduce(my_behind, map(int, behind))

 #利用埃氏筛法筛选出素数
 #产生无限的奇数
 def my_productNumber():
   n = 1
   while 1:
     n += 2
     yield n

 #返回判断是否是素数的函数
 def my_isPrime(n):
     return lambda x: x % n > 0

 #素数发生器
 def my_Primes():
   yield 2
   it = my_productNumber()
   while 1:
     n = next(it)
     yield n
     it = filter(my_isPrime(n), it)

 for n in my_Primes():
   if n < 100:
     print(n)
   else:
     break

 #判断一个数是否回文
 def my_isPalindrome(n):
   return str(n)[::-1] == str(n)
 print(filter(my_isPalindrome, range(1, 1000)))

 #关于装饰器
 import functools

 def log(text=None):
   def decorator(func):
     @functools.wraps(func)
     def wrapper(*args, **kw):
       if text == None:
         # print('call %s()' % func.__name__)
         pass
       else:
         # print('%s %s()' % (text, func.__name__))
         pass
       print('Begin Func↓')
       temp = func(*args, **kw)
       print('End Func↑')
       return temp
     return wrapper
   return decorator

 @log('call')  #相当于now = log('hahaha')(now)
 def now(t):
   print("")
   return t
 now(4)
 print(now.__name__)