英文:
Dictionary popping
问题
我尝试在字典thisdict中如果键不在其中则弹出键，但是我一直收到键错误```pythonuserList = [User(id='1', username='bob'), User(id='2', username='john')]players = {}players['1'] = 'bob'players['4534509345ffgdfgd'] = 'caleb'print(players)# 遍历字典的项for key, value in list(players.items()):found = False# 检查是否在userList中找到匹配项for user in userList:if user.id == key and user.username == value:found = Truebreak# 如果没有找到匹配项，则删除该项if not found:players.pop(key)print(players)
因为Caleb不在thisdict中，所以应该从players中删除。Player具有属性username和id。
英文:
I'm trying to pop they key if it is not in dictionary thisdict but I keep getting a key error
userList = [User(id='1', username='bob'), User(id='2', username='john')]players = {}players['1'] = 'bob'players['4534509345ffgdfgd'] = 'caleb'print(players)for y in players.items():if y not in userList:players.pop(y)print(players)
Caleb should be removed from players because he is not present in thisdict. How do I do this please? Player does have attribute username and id
答案1
得分: 1
假设User对象具有可以访问的username属性，并且您想要修改players字典。
# 生成可接受的名称集合 *一次*player_names = {player.username for player in thisdict}filtered_players = {key: valuefor key, value in players.items()if value.username in player_names}
这将生成一个新的字典，不会修改原始的players字典。
英文:
Assuming User objects have an attribute username that can be accessed and that you want to modify the players dictionary.
# Generating a set of acceptable names *once*player_names = {player.username for player in thisdict}filtered_players = {key: valuefor key: value in players.items()if value.username in player_names}
This generates a new dictionary and does not modify the original players dictionary.
答案2
得分: 0
{k:v for k,v in players.items() if v in thisdict.values()}：这是一个一行代码，可以实现你想要的功能。
英文:
Here is a one liner to do what you want :
{k:v for k,v in players.items() if v in thisdict.values()}
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