Python_collections_OrderedDict有序字典部分功能介绍

OrderedDict():实现字典的固定排序,是字典的子类

import collections
dic = collections.OrderedDict()
dic['k1'] = 3
dic['k2'] = 'nihao'
dic['k3'] = 7
print(dic)

结果：
OrderedDict([('k1', 3), ('k2', 'nihao'), ('k3', 7)])

x.move_to_end():把一个元素移动到最后

import collections
dic = collections.OrderedDict()
dic['k1'] = 3
dic['k2'] = 'nihao'
dic['k3'] = 7
print(dic)
dic.move_to_end('k2')
print(dic)

结果：
OrderedDict([('k1', 3), ('k2', 'nihao'), ('k3', 7)])
OrderedDict([('k1', 3), ('k3', 7), ('k2', 'nihao')])

x.popitem():移除最后一个写入字典的值，并可返回获取

x.pop():移除指定值并可返回获取