python函数递归求和详解_Python函数中多类型传值和冗余参数及函数的递归调用

1.多类型传值和冗余参数

多类型传值：

def fun(x,y):

return x +y

print fun(3,5)

8

print fun(*t)

3

def fun(x,y,z):

return x + y + z

t1 = (1,2,3)

fun(*t1)

6

fun(*(2,4,5))

11

fun(1,*t)

4

print t

(1, 2)

fun(x=1,y=3,z=5)

9

>>> dic = {'x':1,'y':3,'z':6}

>>> fun(**dic)

10

冗余参数：

>>> def fun(x,*args,**kwargs):

... print x

... print args

... print kwargs

...

>>> fun(1)

1

()

{}

>>> fun(1,2)

1

(2,)

{}

>>> fun(1,2,3)

1

(2, 3)

{}

>>> t

(1, 2)

>>> fun(1,2,3,'a',[1,2],*t,a=3,**{'t':11,'p':22})

1

(2, 3, 'a', [1, 2], 1, 2)

{'a': 3, 'p': 22, 't': 11}

2.函数的递归调用

递归的注意事项：

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)

阶乘脚本：

#!/usr/bin/env python

# -*- coding:utf-8 -*-

# @Time: 2018/1/4 11:57

# @Author: Feng Xiaoqing

# @File: jiecheng.py

# ======================

def factorial(n):

sum = 0

for i in range(1,n+1):

sum += i

return sum

print factorial(100)

另外一种方法：

def factorial(n):

if n == 0:

return 1

else:

return n * factorial(n-1)

print factorial(5)

求1-100相加的和：

def factorial(n):

if n == 0:

return 0

else:

return n + factorial(n-1)

print factorial(100)