operator.itemgetter函数：
import operator
>>> help(operator.itemgetter)
Help on class itemgetter in module operator:
class itemgetter(builtins.object)
| itemgetter(item, ...) --> itemgetter object
|
| Return a callable object that fetches the given item(s) from its operand.
| After f = itemgetter(2), the call f(r) returns r[2].
| After g = itemgetter(2, 5, 3), the call g(r) returns (r[2], r[5], r[3])
|
| Methods defined here:
|
| __call__(self, /, *args, **kwargs)
| Call self as a function.
|
| __getattribute__(self, name, /)
| Return getattr(self, name).
|
| __reduce__(...)
| Return state information for pickling
|
| __repr__(self, /)
| Return repr(self).
|
| ----------------------------------------------------------------------
| Static methods defined here:
|
| __new__(*args, **kwargs) from builtins.type
| Create and return a new object. See help(type) for accurate signature.
operator模块提供的itemgetter函数用于获取对象的哪些维的数据，参数为一些序号（即需要获取的数据在对象中的序号）
a=[1,2,3]
b=operator.itemgetter(1)#定义函数b，获取对象的第一个域的值
b(a)
b=operator.itemgetter(1,0)#定义函数b，获取对象的第1个域和第0个域的值
b(a)
运行结果：
a = [1,2,3]
>>> b = operator.itemgetter(1)
>>> b(a)
2
>>> b = operator.itemgetter(1,0)
>>> b(a)
(2, 1)
