一、定义

def functionName([arg1,arg2,...]):
    code

二、示例

#!/usr/bin/python
#coding:utf8
#coding=utf8
#encoding:utf8
#encoding=utf8

def fun(x=3,y=‘甜‘):
    print ‘生成一个‘,x,‘元‘,y,‘口味的蛋糕‘

fun()

fun(10)

fun(y=‘奶油‘)

冗余参数：

#!/usr/bin/python

def f(name="jim",age=20):
    print "name:%s age:%s" % (name,age)

t=(‘tom‘, 25)
d={‘age‘:25,‘name‘:‘lucy‘}

f(*t)
#name:tom age:25

f(**d)
#name:lucy age:25

def f1(x,*args):
    print x,args

t1=(‘tom‘,25,‘male‘)
f1(*t1)
#tom (25,‘male‘)

def f2(x,**args):
    print x,args

d1={‘x‘:1,‘y‘:2}
f2(**d1)
#1 {‘y‘:2}

def f3(x,*arg1,**arg2):
    print x
    print arg1
    print arg2

f3(1,2,3,a=1,b=2,c=3)
#1
#(2,3)
#{‘a‘:1,‘b‘:2,‘c‘:3}