#yyds干货盘点#python任意实参列表

调用函数时，使用任意数量的实参是最少见的选项。这些实参包含在元组中（详见 ​​元组和序列​​ ）。在可变数量的实参之前，可能有若干个普通参数：

def write_multiple_items(file, separator, *args):
file.write(separator.join(args))def concat(*args, sep="/"):
return sep.join(args)
concat("earth", "mars", "venus")
'earth/mars/venus'
concat("earth", "mars", "venus", sep=".")
'earth.mars.venus'

解包实参列表

函数调用要求独立的位置参数，但实参在列表或元组里时，要执行相反的操作。例如，内置的 ​​range()​ 函数要求独立的 start 和 stop 实参。如果这些参数不是独立的，则要在调用函数时，用 * 操作符把实参从列表或元组解包出来：

list(range(3, 6)) # normal call with separate arguments
[3, 4, 5]
args = [3, 6]
list(range(*args)) # call with arguments unpacked from a list
[3, 4, 5]

同样，字典可以用 ** 操作符传递关键字参数：

def parrot(voltage, state='a stiff', action='voom'):
print("-- This parrot wouldn't", action, end=' ')
print("if you put", voltage, "volts through it.", end=' ')
print("E's", state, "!")

d = {"voltage": "four million", "state": "bleedin' demised", "action": "VOOM"}
parrot(**d)
-- This parrot wouldn't VOOM if you put four million volts through it. E's bleedin' demised !