django中的*args 与 **kwargs使用介绍

def foo(*args,**kwargs): print 'args=',args print 'kwargs=',kwargs print '**********************' if __name__=='__main__': foo(1,2,3) foo(a=1,b=2,c=3) foo(1,2,3,a=1,b=2,c=3) foo(1,'b','c',a=1,b='b',c='c')

args= (1, 2, 3) kwargs= {} **********************
args= () kwargs= {'a': 1, 'c': 3, 'b': 2} **********************
args= (1, 2, 3) kwargs= {'a': 1, 'c': 3, 'b': 2} **********************
args= (1, 'b', 'c') kwargs= {'a': 1, 'c': 'c', 'b': 'b'} **********************

DataFrame.groupby(by=None, axis=0, level=None, as_index= True, sort=True, group_keys=True, squeeze=False, observed=False, **kwargs)

def test_args(normal_arg, *args):
 print("first normal arg:" + normal_arg)
 for arg in args:
  print("another arg through *args :" + arg)
test_args("normal", "python", "java", "C#")

first normal arg: normal
another arg through *args : python
another arg through *args : java
another arg through *args :C#

def test_kwargs(**kwargs):
 if kwargs is not None:
  for key, value in kwargs.iteritems():
   print("{} = {}".format(key,value))
  # Or you can visit kwargs like a dict() object
  # for key in kwargs:
  # print("{} = {}".format(key, kwargs[key]))
test_kwargs(name="python", value="5")

name = python
value = 5

def normal_func(arg1, arg2, arg3):
 print("arg1: " + arg1)
 print("arg2: " + arg2)
 print("arg3: " + arg3)
normal_func("python", 1, 3)

# 使用*args
args_list = ("python", 1, 3)
normal_func(*args_list)
# 使用**kwargs
kwargs_dict = {"arg3": 3, "arg1": "python", "arg2": 1}
normal_func(**kwargs_dict)

arg1: python
arg2: 1
arg3: 3