如何从带有parent_id的字典中创建带有子项的字典 [英] How to create dict with childrens from dict with parent_id
本文介绍了如何从带有parent_id的字典中创建带有子项的字典的处理方法,对大家解决问题具有一定的参考价值,需要的朋友们下面随着小编来一起学习吧!
问题描述
如何从此字典中获取信息:
How to get from this dict:
cats = [
{'parent_id': False, 'id': 1, 'title': u'All'},
{'parent_id': False, 'id': 2, 'title': u'Toys'},
{'parent_id': 2, 'id': 3, 'title': u'Toypads'},
{'parent_id': 3, 'id': 4, 'title': u'Green'},
]
像这样吗?
cats = [
{'parent_id': False, 'id': 1, 'title': u'All'},
{'parent_id': False,
'children': [{'parent_id': 2,
'children': [{'parent_id': 3, 'id': 4,
'title': u'Green'}],
'id': 3, 'title': u'Toypads'},
[{'parent_id': 3, 'id': 4, 'title': u'Green'}]],
'id': 2, 'title': u'Toys'}
]
我需要它在Jinja2中构建菜单\子菜单. 我写了一个非常糟糕的代码.这将是一个更优雅的解决方案.
I need it to build a menu\sub-menu in Jinja2. I wrote a very bad code. It would be a more elegant solution.
q = dict(zip([i['id'] for i in cats], cats))
from collections import defaultdict
parent_map = defaultdict(list)
for item in q.itervalues():
parent_map[item['parent_id']].append(item['id'])
def tree_level(parent):
for item in parent_map[parent]:
yield q[item]
sub_items = list(tree_level(item))
if sub_items:
for ca in cats:
if ca['id'] == item:
cats[cats.index(ca)]['children'] = sub_items
for s_i in sub_items:
try:
for ca_del_child in cats:
if ca_del_child['id'] == s_i['id']:
del cats[cats.index(ca_del_child)]
except:
pass
yield sub_items
for i in list(tree_level(False)):
pass
推荐答案
这是一个相当简洁的解决方案:
Here is a fairly concise solution:
cats = [{'parent_id': False, 'id': 1, 'title': u'All'},
{'parent_id': False, 'id': 2, 'title': u'Toys'},
{'parent_id': 2, 'id': 3, 'title': u'Toypads'},
{'parent_id': 3, 'id': 4, 'title': u'Green'},]
cats_dict = dict((cat['id'], cat) for cat in cats)
for cat in cats:
if cat['parent_id'] != False:
parent = cats_dict[cat['parent_id']]
parent.setdefault('children', []).append(cat)
cats = [cat for cat in cats if cat['parent_id'] == False]
请注意,通常不需要与False进行比较,但是如果您的猫的id或parent_id为0,则应在此处使用它们.在这种情况下,对于没有父母的猫,我会使用None
而不是False
.
Note that the comparisons to False are generally not necessary, but they should be used here in case you had a cat with 0 as its id or parent_id. In this case I would use None
instead of False
for a cat with no parent.
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