多类型传值和冗余参数+递归调用

In [3]: def fun(x,y):       ##定义一个fun函数
   ...:     print x + y
   ...:     

In [4]: t =(1,2)        ##设定一个 t元祖

In [5]: fun(t)      ##直接把t元祖的值导入到函数中是不可以的
---------------------------------------------------------------------------
TypeError                                 Traceback (most recent call last)
<ipython-input-5-cc8bac9e3135> in <module>()
----> 1 fun(t)

TypeError: fun() takes exactly 2 arguments (1 given)

In [6]: fun(*t)     ##这样 在括号内添加 *号就可以顺利的传入元祖的元素
3

In [7]: def aa(x,y,z):
   ...:     return x+y+z
   ...: 

In [8]: t1 = (1,2,3)

In [9]: aa(*t1)
Out[9]: 6

In [10]: aa(*(1,2,3))
Out[10]: 6

In [11]: aa(x=1,y=3,z=5)
Out[11]: 9

In [12]: dic = {'x':1,'y':2,'z':3}

In [14]: aa(**dic)
Out[14]: 6

In [2]: def aa(x, *args, **kwargs):     ##定义三个参数
   ...:     print x
   ...:     print args
   ...:     print kwargs
   ...:     

In [3]: aa(11)  ##传入一个参数
11
()      ##第二个参数是列表
{}      ##第三个参数是字典

In [4]: aa(1,2,3)
1
(2, 3)
{}

In [5]: aa(1,2,'a',[1,2])
1
(2, 'a', [1, 2])
{}

In [7]: aa(1,2,'a',[1,2],y=22,z=43)     ##只有以字典或=的方式才会传到字典里面，其它的均传到列表里
1
(2, 'a', [1, 2])
{'y': 22, 'z': 43}

[[email protected] python]# cat 3.py 
#! /usr/bin/python

def factorial(n):
    sum = 1
    for i in xrange(1, n+1):
        sum *= i
    return sum
print factorial(int(raw_input("pls input a number: ")))

执行结果：
[[email protected] python]# python 3.py 
pls input a number: 3
6
[[email protected] python]# python 3.py 
pls input a number: 5
120

必须有最后的默认结果
        if n == 0
递归参数必须向默认结果收敛的：
        factorial(n-1)

[[email protected] python]# cat 3.py 
#! /usr/bin/python

def factorial(n):
    if n == 0:
        return 1
    else:
        return n * factorial(n-1)
print factorial(int(raw_input("pls input a number: ")))

执行结果：
[[email protected] python]# python 3.py 
pls input a number: 5
120
[[email protected] python]# python 3.py 
pls input a number: 3
6