最近了解到*和**运算符的用法，特此小记。
最开始遇到的情形是这样的：我从另一个地方得到了一个tuple a：
a = (1,2)想把这个tuple里的值作为另一个函数f的参数传给它，理论上完全可以用[]把每个值取出来再一个一个传给函数：
def f(x, y):
return x + y
f(a[0], a[1])但这样写也太蠢了，而且当这里参数的个数不是两个而是很多的时候，这样写也太麻烦了。Google一番之后了解到有*运算符这种神奇的东西，有了它，上面的写法可以简化为：
f(*a)在官方文档中也有相关的说明：
4.7.4. Unpacking Argument Lists
The reverse situation occurs when the arguments are already in a list or tuple but need to be unpacked for a function call requiring separate positional arguments. For instance, the built-in range() function expects separate start and stop arguments. If they are not available separately, write the function call with the *-operator to unpack the arguments out of a list or tuple:
>>> 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] 文档中还提了**的用法：
>>> 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 !在自己尝试的过程中也发现了两个有意思的用法：
>>> a = [1,2,3]
>>> print(a)
>>> [1, 2, 3]
>>> print(*a)
>>> 1 2 3>>> a = [1,2]
>>> [4,5,a,7,8]
>>> [4, 5, [1, 2], 7, 8]
>>> [4,5,*a,7,8]
>>> [4, 5, 1, 2, 7, 8]