Python function parameter * args ** kwargs usage example

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# Coding = utf8
_ Author _ = 'admin'

# When the parameters of a function are unknown, you can use * args and ** kwargs. * Args has no key value. ** kwargs has a key value.

Def fun_var_args (farg, * args ):
Print 'args: ', farg
For value in args:
Print 'another arg: ', value

# * Args can be used as a list or tuple consisting of multiple variables.
Fun_var_args (1, 'two', 3, None)

# Args: 1
# Another arg: two
# Another arg: 3
# Another arg: None

Def fun_var_kwargs (farg, ** kwargs ):
Print 'args: ', farg
For key in kwargs:
Print 'another keyword arg: % s: % s' % (key, kwargs [key])

# Myarg1, myarg2, and myarg3 are considered as keys. ** kwargs can be considered as a dictionary that can hold multiple keys and values.
Fun_var_kwargs (1, myarg1 = 'two', myarg2 = 3, myarg3 = None)
# Output:
# Args: 1
# Another keyword arg: myarg1: two
# Another keyword arg: myarg2: 3
# Another keyword arg: myarg3: None

Def fun_args (arg1, arg2, arg3 ):
Print 'arg1: ', arg1
Print 'arg2: ', arg2
Print 'arg3: ', arg3

Myargs = ['1', 'two', None] # definition list
Fun_args (* myargs)

# Output:
# Arg1: 1
# Arg2: two
# Arg3: None

Mykwargs = {'arg1': '1', 'arg2': 'two', 'arg3': None} # define the dictionary type
Fun_args (** mykwargs)

# Output:
# Arg1: 1
# Arg2: two
# Arg3: None

# Both have
Def fun_args_kwargs (* args, ** kwargs ):
Print 'args: ', args
Print 'kwargs: ', kwargs

Args = [1, 2, 3, 4]
Kwargs = {'name': 'beginman', 'age': 22}
Fun_args_kwargs (args, kwargs)
# Args: ([1, 2, 3, 4], {'age': 22, 'name': 'beginman '})
# Kwargs :{}

Fun_args_kwargs (1, 2, 3, a = 100)
# Args: (1, 2, 3)
# Kwargs: {'A': 100}

Fun_args_kwargs (* (1, 2, 3, 4), ** {'A': None })
# Args: (1, 2, 3, 4)
# Kwargs: {'A': None}