python 赋值魔法

序列解包：

>>> x,y,z = 1, 2, 3
>>> print(x, y, z)
1 2 3

>>> a,b, *reset = [1,2,3,4]
>>> print(a,b,reset)
1 2 [3, 4]

链式赋值：

x = y = function

增量赋值：

>>> x = 2
>>> x +=1
>>> x
3
>>> x *=2
>>> x
6

>>> fnord = 'foo'
>>> fnord +='bar'
>>> fnord
'foobar'
>>> fnord *=2
>>> fnord
'foobarfoobar'