你希望函数的某些参数强制使用关键字参数传递:

你希望函数的某些参数强制使用关键字参数传递:

将强制关键字参数放到某个*参数或者当个*后面就能达到这种效果:

def dog(name, host, *, age):
    print(name, host, age)
参数中有一个 “*” 号，在该符号之后的所有参数（可一至多个）均被称为强制关键字参数，如果按照位置参数的方式对这些参数传值：


[root@node01 python]# cat s1.py 
def dog(name, host, *, age):
    print(name, host, age)
dog('a','b',23)


[root@node01 python]# python3.6 s1.py 
Traceback (most recent call last):
  File "s1.py", line 3, in <module>
    dog('a','b',23)
TypeError: dog() takes 2 positional arguments but 3 were given
[root@node01 python]# 

[root@node01 python]# cat s1.py 
def dog(name, host, *, age):
    print(name, host, age)
dog('dobi', 'xuzhoufeng', age = 2)


[root@node01 python]# python3.6 s1.py 
dobi xuzhoufeng 2


[root@node01 python]# cat s2.py 
def recv(maxsize, *, block):
    print (maxsize,block)
recv(1,2)
[root@node01 python]# 
[root@node01 python]# python3.6 s2.py 
Traceback (most recent call last):
  File "s2.py", line 3, in <module>
    recv(1,2)
TypeError: recv() takes 1 positional argument but 2 were given

[root@node01 python]# cat s2.py 
def recv(maxsize, *, block):
    print (maxsize,block)
recv(1,block=2)
[root@node01 python]# python3.6 s2.py 
1 2