将字典值转换为Python中的键

Question

groups_per_user 函数接收一个字典，其中包含组名称和用户列表。用户可以属于多个组。填写空白以返回一个字典，其中用户作为键，其组列表作为值def groups_per_user(group_dictionary):    user_groups = {}    for key,values in group_dictionary.items():        for users in values:            user_groups[users] = user_groups.get(users,0)+1    return(user_groups)print(groups_per_user({"local": ["admin", "userA"],"public":  ["admin", "userB"],"administrator":         ["admin"] }))# output must be {'admin':["local","public","administrator"],'userA':"local" ,'userB':"public"}#output I am getting {'admin': 3, 'userA': 1, 'userB': 1}

Answer 1

您可以迭代当前dict并反转键值对：

d = {"local": ["admin", "userA"], "public":  ["admin", "userB"], "administrator": ["admin"] }

res = {}

for k,v in d.items():

    for e in v:

        if e in res:

            res[e].append(k)

        else:

            res[e] = [k]

print(res)

输出：

{'admin': ['public', 'administrator', 'local'], 'userB': ['public'], 'userA': ['local']}   

Answer 2

请尝试下面的程序。它只是迭代 group_dictionary 的所有元素并构造 user_dictionary。

def groups_per_user(group_dictionary):

    user_groups=dict([(a,[]) for a in sum(group_dictionary.values(),list())])

    for u in user_groups:

        for g in group_dictionary:

            if u in group_dictionary[g]:

                user_groups[u].append(g)

    return(user_groups)

print(groups_per_user({"local": ["admin", "userA"],"public":  ["admin", "userB"],"administrator":         ["admin"] }))

输出

{'admin': ['local', 'public', 'administrator'], 'userA': ['local'], 'userB': ['public']}