无序字典和有序字典

from collections import OrderedDict

from collections import OrderedDict

OrderedDict就是一个类 需要需用 先进行 实例化

od = OrderedDict()然后和字典的用法是一样的

from collections import OrderedDictod = OrderedDict()od['k1'] = 'v1'od['k2'] = 'v2'od['k3'] = 'v3'for k, v in od.items():    print('k={},v={}'.format(k, v))

显示的结果就是

k=k1,v=v1 k=k2,v=v2 k=k3,v=v3

这就是有序字典了  有序字典就是按照插入数据的顺序输出的我的应用场景 是对一级菜单排序

from collections import OrderedDict  @register.inclusion_tag('menu.html') def menu(request):     od = OrderedDict()     menu_dict = request.session.get(settings.MENU_SESSION_KEY)     # url = request.path_info     # for i in menu_list:     #     if re.match(r'{}$'.format(i['url']), url):     #         i['class'] = 'active'     #         break     # print(menu_dict.values())     menu_list = sorted(menu_dict, key=lambda x: menu_dict[x]['weight'], reverse=True)     # print(menu_list)     for key in menu_list:         od[key] = menu_dict[key]      return {'menu_list': od.values()}