使用 python 遍历出数据库中三级菜单

昨天面试的时候提到了这个问题，但是由于面试时有点紧张，加上之前没做过这个，没写出来，今天补出来。

code

a=[
    {"id":1,"menu_name":"菜单1","pid":0},
    {"id":2,"menu_name":"菜单1-1","pid":1},
    {"id":3,"menu_name":"菜单1-2","pid":1},
    {"id":4,"menu_name":"菜单1-3","pid":1},
    {"id":5,"menu_name":"菜单1-1-1","pid":2},
    {"id":6,"menu_name":"菜单1-1-2","pid":2},
    {"id":7,"menu_name":"菜单2","pid":0},
    {"id":8,"menu_name":"菜单2-1","pid":7},
    {"id":9,"menu_name":"菜单2-2","pid":7},
    {"id":10,"menu_name":"菜单2-3","pid":7},
    {"id":11,"menu_name":"菜单2-1-1","pid":8},
    {"id":12,"menu_name":"菜单2-1-2","pid":8},
    {"id":13,"menu_name":"菜单2-2-1","pid":9},
    {"id":14,"menu_name":"菜单2-3-1","pid":10},
    {"id":15,"menu_name":"菜单2-3-2","pid":10},
    {"id":16,"menu_name":"菜单2-3-3","pid":10},
    {"id":17,"menu_name":"菜单2-3-4","pid":10}
]


def get_menu(a):
    dic_test={}
    for tcc in a:
        if(tcc["pid"]==0):
            dic_test[tcc["menu_name"]]={"id":tcc["id"],"child":[]}

    for i in dic_test:
        index1=dic_test[i]["id"]
        menu_name1=i
        for j in a:
            if(j["pid"]==index1):
                dic_test[menu_name1]["child"].append({j["menu_name"]:{"id":j["id"],"child":[]}})

        if(dic_test[menu_name1]["child"]):
            for indexc,k in enumerate(dic_test[menu_name1]["child"]):
                for l in a:
                    for x,b in k.items():
                        if(b["id"]==l["pid"]):
                            dic_test[menu_name1]["child"][int(indexc)][x]["child"].append({l["menu_name"]:{"id":l["id"],"child":[]}})
    return dic_test

print(get_menu(a))

#输出
'''
{
    '菜单1': {
        'id': 1,
        'child': [{
            '菜单1-1': {
                'id': 2,
                'child': [{
                    '菜单1-1-1': {
                        'id': 5,
                        'child': []
                    }
                }, {
                    '菜单1-1-2': {
                        'id': 6,
                        'child': []
                    }
                }]
            }
        }, {
            '菜单1-2': {
                'id': 3,
                'child': []
            }
        }, {
            '菜单1-3': {
                'id': 4,
                'child': []
            }
        }]
    },
    '菜单2': {
        'id': 7,
        'child': [{
            '菜单2-1': {
                'id': 8,
                'child': [{
                    '菜单2-1-1': {
                        'id': 11,
                        'child': []
                    }
                }, {
                    '菜单2-1-2': {
                        'id': 12,
                        'child': []
                    }
                }]
            }
        }, {
            '菜单2-2': {
                'id': 9,
                'child': [{
                    '菜单2-2-1': {
                        'id': 13,
                        'child': []
                    }
                }]
            }
        }, {
            '菜单2-3': {
                'id': 10,
                'child': [{
                    '菜单2-3-1': {
                        'id': 14,
                        'child': []
                    }
                }, {
                    '菜单2-3-2': {
                        'id': 15,
                        'child': []
                    }
                }, {
                    '菜单2-3-3': {
                        'id': 16,
                        'child': []
                    }
                }, {
                    '菜单2-3-4': {
                        'id': 17,
                        'child': []
                    }
                }]
            }
        }]
    }
}
'''