[Python] 파이썬 *args,**kwargs 의미 (Asterisk(*))
*args
- list of arguments - as positional arguments
- 파라미터를 몇개를 받을지 모르는 경우 사용한다.
- args 는 튜플 형태로 전달된다.
<ex>-------------------------
def print_param(*args):
print args
for p in args:
print p
print_param('a', 'b', 'c', 'd')
#('a', 'b', 'c', 'd')
#a
#b
#c
#d
-------------------------
**kwargs
- dictionary - whose keys become separate keyword arguments and the values become values of these arguments.
- 파라미터 명을 같이 보낼 수 있다.
- kwargs는 딕셔너리 형태로 전달된다.
<ex>-------------------------
def print_param2(**kwargs):
print kwargs
print kwargs.keys()
print kwargs.values()
for name, value in kwargs.items():
print "%s : %s" % (name, value)
print_param2(first = 'a', second = 'b', third = 'c', fourth = 'd')
#{'second': 'b', 'fourth': 'd', 'third': 'c', 'first': 'a'}
#['second', 'fourth', 'third', 'first']
#['b', 'd', 'c', 'a']
#second : b
#fourth : d
#third : c
#first : a
-------------------------
응용1
<ex>-------------------------
def print_param3(*args, **kwargs):
print args
print kwargs
print_param3('a', 'b')
#('a', 'b')
#{}
print_param3(third = 'c', fourth = 'd')
#()
#{'fourth': 'd', 'third': 'c'}
print_param3('a', 'b', third = 'c', fourth = 'd')
#('a', 'b')
#{'fourth': 'd', 'third': 'c'}
-------------------------
응용2
<ex>-------------------------
def print_param4(a, b, c):
print a, b, c
p = ['a', 'b', 'c']
print_param4(*p)
#a b c
p2 = {'c' : '1', 'a' : '2', 'b' : '3'}
print_param4(**p2)
#2 3 1
-------------------------
참고:
https://jhproject.tistory.com/109
https://stackoverflow.com/questions/3394835/use-of-args-and-kwargs