django中的构造字典(二级菜单，评论树，购物车)
1.构造父子结构：
1.1需求样式
客户列表 customer_list /customer/list/ -----> 添加客户 customer_add /customer/add/ -----> 编辑客户 customer_edit /customer/edit/(?P<cid>\d+)/ -----> 删除客户 customer_del /customer/del/(?P<cid>\d+)/ -----> 批量导入客户 customer_import /customer/import/ -----> 下载客户模板 customer_tpl /customer/tpl/ 账单列表 payment_list /payment/list/ -----> 添加账单 payment_add /payment/add/ -----> 编辑账单 payment_edit /payment/edit/(?P<pid>\d+)/ -----> 删除账单 payment_del /payment/del/(?P<pid>\d+)/
django中构造方式： ———>最重要的其实就是这里对于表结构的考虑
{ 1:{ 'title':'账单列表', 'url':'/payment/list/', 'name':'payment_list', children:[ {'title':'删除账单','url':'/payment/list/','name':'payment_list'}, {'title':'编辑账单','url':'/payment/list/','name':'payment_list'}, {'title':'添加账单','url':'/payment/list/','name':'payment_list'}, ] }, 2:{ 'title':'客户列表', 'url':'/payment/list/', 'name':'payment_list', children:[ {'title':'下载客户模板','url':'/payment/list/','name':'payment_list'}, {'title':'下载客户模板','url':'/payment/list/','name':'payment_list'}, {'title':'下载客户模板','url':'/payment/list/','name':'payment_list'}, ] } }
models.py
class Menu(models.Model): """ 菜单表 """ title = models.CharField(max_length=32,unique=True) icon = models.CharField(max_length=32) def __str__(self): return self.title class Permission(models.Model): """ 权限表 """ title = models.CharField(verbose_name='标题', max_length=32) url = models.CharField(verbose_name='含正则的URL', max_length=128) name = models.CharField(verbose_name='URL别名',max_length=32,null=True,blank=True) parent = models.ForeignKey(verbose_name='父权限',to='Permission',null=True,blank=True) menu = models.ForeignKey(verbose_name='菜单',to='Menu',null=True,blank=True) def __str__(self): return self.title
# 有parent_id没有menu_id表示是具有三级菜单
# 有menu_id没有parent_id则表示是具有二级菜单
# 两者不能同时都有值
表数据
menu：
permission：
构造方式一：
def role_bbb(request): permission_queryset = models.Permission.objects.all().values("id","title","url","name","parent_id") root_permission_dict = {} for item in permission_queryset: if not item["parent_id"]: root_permission_dict[item["id"]] = { "url":item["url"], "title":item["title"], "name":item["name"], "children":[], } for item in permission_queryset: parent_id = item['parent_id'] if parent_id: root_permission_dict[parent_id]['children'].append({ 'title': item['title'], 'url': item['url'], 'name': item['name'] }) # 打印测试 for root in root_permission_dict.values(): print(root["title"],root['name'],root['url']) for node in root['children']: print('----->', node['title'], node['name'], node['url']) return HttpResponse("+++++")
构造方式二:
def role_bbb(request): root_permission_dict = {} query = models.Permission.objects.filter(menu__isnull=False).values('id','title','url','name','parent_id') for item in query: root_permission_dict[item["id"]] = { 'title': item['title'], 'url': item['url'], 'name': item['name'], 'children': [] } models.Permission.objects.filter(menu__isnull=True).values('id','title','url','name','parent_id') for item in query_dic: parent_id = item['parent_id'] if parent_id: root_permission_dict[parent_id]['children'].append({ 'title': item['title'], 'url': item['url'], 'name': item['name'] }) # 打印测试 for root in root_permission_dict.values(): print(root["title"],root['name'],root['url']) for node in root['children']: print('----->', node['title'], node['name'], node['url']) return HttpResponse("+++++")
构造方式三：
def role_bbb(request): permission_queryset = models.Permission.objects.all().values("id", "title", "url", "name", "parent_id") root_permission_dict = {} for item in permission_queryset: if not item['parent_id']: root_permission_dict[item['id']] = { 'title': item['title'], 'url': item['url'], 'name': item['name'], 'children': [] } else: pid = item["parent_id"] root_permission_dict[pid]["children"].append({ 'title': item['title'], 'url': item['url'], 'name': item['name'] }) return HttpResponse("+++++")
2.构造家族结构 ------>用于构造评论树
2.1需求
在实际应用中，我们对于一篇文章的评论通常包含了根评论，根评论下可以具有多个子评论，我们现在才可以通过构造数据结构来实现他所具有的功能
构造方式：
comment_list = [ {'id': 1, 'title': '根评论', 'pid': None}, {'id': 2, 'title': '根评论', 'pid': None}, {'id': 3, 'title': 'id是1下的评论', 'pid': 1}, {'id': 4, 'title': 'id是2下的评论', 'pid': 2}, {'id': 5, 'title': 'id是1下的评论', 'pid': 1}, {'id': 6, 'title': 'id是3下的评论', 'pid': 3}, {'id': 7, 'title': 'id是6下的评论', 'pid': 6}, ]
演示代码：
comment_dict = {} for item in comment_list: item['children'] = [] comment_dict[item['id']] = item for row in comment_list: if not row['pid']: # 判断根评论 continue # 跳过此次循环 pid = row['pid'] # 获取pid # 最加到children中 comment_dict[pid]['children'].append(row) print(comment_dict)
效果：
{ 1: { 'id': 1, 'title': '根评论', 'pid': None, 'children': [{ 'id': 3, 'title': 'id是1下的评论', 'pid': 1, 'children': [{ 'id': 6, 'title': 'id是3下的评论', 'pid': 3, 'children': [{ 'id': 7, 'title': 'id是6下的评论', 'pid': 6, 'children': [] }] }] }, { 'id': 5, 'title': 'id是1下的评论', 'pid': 1, 'children': [] }] }, 2: { 'id': 2, 'title': '根评论', 'pid': None, 'children': [{ 'id': 4, 'title': 'id是2下的评论', 'pid': 2, 'children': [] }] }, 3: { 'id': 3, 'title': 'id是1下的评论', 'pid': 1, 'children': [{ 'id': 6, 'title': 'id是3下的评论', 'pid': 3, 'children': [{ 'id': 7, 'title': 'id是6下的评论', 'pid': 6, 'children': [] }] }] }, 4: { 'id': 4, 'title': 'id是2下的评论', 'pid': 2, 'children': [] }, 5: { 'id': 5, 'title': 'id是1下的评论', 'pid': 1, 'children': [] }, 6: { 'id': 6, 'title': 'id是3下的评论', 'pid': 3, 'children': [{ 'id': 7, 'title': 'id是6下的评论', 'pid': 6, 'children': [] }] }, 7: { 'id': 7, 'title': 'id是6下的评论', 'pid': 6, 'children': [] } }
这样可以构造，但是明显显得累赘，把子评论也全都打印了一遍
以上在做改进:
comment_dict = {} for item in comment_list: item['children'] = [] comment_dict[item['id']] = item result = [] for row in comment_list: if not row['pid']: # 判断根评论 result.append(row) # 添加到列表 else: pid = row['pid'] # 最加到children中 comment_dict[pid]['children'].append(row) print(result)
json序列化效果(想使用序列化格式工具转化，需要先转换成json格式才行，通过json.dumps)：
[{ "title": "根评论", "pid": null, "id": 1, "children": [{ "title": "id是1下的评论", "pid": 1, "id": 3, "children": [{ "title": "id是3下的评论", "pid": 3, "id": 6, "children": [{ "title": "id是6下的评论", "pid": 6, "id": 7, "children": [] }] }] }, { "title": "id是1下的评论", "pid": 1, "id": 5, "children": [] }] }, { "title": "根评论", "pid": null, "id": 2, "children": [{ "title": "id是2下的评论", "pid": 2, "id": 4, "children": [] }] }]
