无极限分类,迭代分类,递归分类

res = []
#递归分类法
def get_con(data,parent_id=0,clas=True):
    if clas:
        res.clear()
    for i in data:
        if i["parent_id"] == parent_id:
            res.append(i)
            get_con(data,parent_id=i["cat_id"],clas=False)
    return res

res2 = get_con(data)
print(res2)
#迭代分类法
data=[
    {"cat_id":1,"name":"北京","parent_id":0},
    {"cat_id":2,"name":"上海","parent_id":0},
    {"cat_id":3,"name":"沙河","parent_id":1},
    {"cat_id":4,"name":"sb镇","parent_id":3},
    {"cat_id":5,"name":"昌平","parent_id":1},
    {"cat_id":6,"name":"青浦","parent_id":2},
]
def get_tree(data):
    lists = []
    tree = {}
    for i in data:
        tree[i["cat_id"]]=i
        #首先给tree 赋值 k为 data内的cat_id,v为data的每一条数据
    for dic in data:
        data_num = dic["parent_id"]
        if not data_num:
            lists.append(tree[dic["cat_id"]])
            #取出parent_id为零的数据 只有两条 取出添加到lists
        else:
            if "chiden" not in tree[data_num]:
                #判断这个字典里面是不是有这个字段
                tree[data_num]["chiden"]=[]
                #没有就添加然后给这个字段变成一个列表
            tree[data_num]["chiden"].append(tree[dic["cat_id"]])
    return lists
ress = get_tree(data)
for i in ress:
    print(ress)