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("2015")
  return t
now(4)
print(now.__name__)