operator.itemgetter函數(shù)：
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模塊提供的itemgetter函數(shù)用于獲取對(duì)象的哪些維的數(shù)據(jù)，參數(shù)為一些序號(hào)（即需要獲取的數(shù)據(jù)在對(duì)象中的序號(hào)）
a=[1,2,3]
b=operator.itemgetter(1)#定義函數(shù)b，獲取對(duì)象的第一個(gè)域的值
b(a)
b=operator.itemgetter(1,0)#定義函數(shù)b，獲取對(duì)象的第1個(gè)域和第0個(gè)域的值
b(a)
運(yùn)行結(jié)果：
a = [1,2,3]
>>> b = operator.itemgetter(1)
>>> b(a)
2
>>> b = operator.itemgetter(1,0)
>>> b(a)
(2, 1)
