python传递参数方式小结

def myprint(*commends,**map):  
 for comm in commends:  
 print comm  
 for key in map.keys():  
 print key,map[key]  
myprint("hello","word",username="tian",name="wei")

hello
word
username tian
name wei

def parrot(voltage="fff",state='a stiff',action='voom',type='Norwegian Blue'):
 print "-- This parrot wouldn't", action,  
 print "if you put", voltage, "volts through it." 
 print "-- Lovely plumage, the", type  
 print "-- It's", state, "!" 
parrot(1000)#可以  
parrot(action = 'VOOOOOM', voltage = 1000000)
#可以，都是key-value方法  
parrot('a thousand', state = 'pushing up the daisies')
#可以，第一个实参为直接传入法，后面无所谓了  
parrot('a million', 'bereft of life', 'jump')
#可以，都是传值，而且由于形参都有默认值，则按顺序一个个替换  
parrot(voltage="33","ff","abc")
# 不可以，第一个为Key-value传值法，以后的都必须是

def a(x,y): 
  print x,y

def a(x,y=3):
  print x,y

def a(*x):  
  # 定义一个名为x的元组

def a(*t):  
  print x 

>a(1) 
(1,) 
>a() 
None 
>a(1,2,3) 
(1,2,3)

def y(*r):
  x = 0
  for t in r:
    x += t
  print x

def a(**b):  
  print b 

>a() 
None 
>a(x=1,y=2) 
{'y':2,'x':1}
#注意遍历返回的顺序与形参位置顺序相反
>a(1,2) #error

def a(**x):  
  print x.get('y')

>a(x=1,y=2) 
2 
>a(x=1) 
None 
>a(x=1,b=2)
None