通過python 3.x中的字典循環列表

Question

我意識到還有其他與此類似的問題，但我不太明白。

假設有一本字典：

fav_food = {'jen':'pizza','eric':'burrito','jason':'spaghetti','tom':'mac'}  

然后有一個列表：

users = ['jason', 'phil', 'jen', 'ben']  

這里的情況是

if a user in the list 'users' is in the dict. 'fav_food.keys()',  
then print(the user + " likes" + fav_food[the user])  
if a user in the list 'users' is not in the dict. 'fav_food.keys()',  
then print(the user + " hasn't taken the poll")

回報應該是：

Jason likes Spaghetti  
Phil hasn't taken the poll  
Jen likes Pizza  
Ben hasn't taken the poll  

我想使用“ for”循環，並以某種方式遍歷字典...但是無論我做什么，我都會不斷出錯。
如果可能的話，我寧願以最“ Python”的方式來做。

非常感謝您的幫助！

Answer 1

你的意思是像

for user in users:
    try:
        print('{} likes {}'.format(user, fav_food[user]))
    except KeyError:
        print("{} hasn't taken the poll".format(user))

這將遍歷所有用戶，如果特定用戶沒有最喜歡的食物 ，那么它只會打印您所說的內容。

Answer 2

你可以試試這個

for user in users:
    if user in fav_food.keys():
        print(user.capitalize(),"likes",fav_food[user].capitalize())
    else:
        print(user.capitalize(),"hasn't taken the poll")

這將輸出為-

Jason likes Spaghetti
Phil hasn't taken the poll
Jen likes Pizza
Ben hasn't taken the poll

Answer 3

fav_food = {'jen':'pizza','eric':'burrito','jason':'spaghetti','tom':'mac'}  
users = ['jason', 'phil', 'jen', 'ben'] 

for user in users:
    print(f"{user} likes {fav_food[user]}" if fav_food.get(user, None) else f"{user} hasn't taken the poll yet")

就像魅力一樣工作，但要記住，如果用戶將空字符串作為自己喜歡的食物，它會說他們沒有參加調查