通过python 3.x中的字典循环列表

Question

我意识到还有其他类似的问题，但我不太明白。假设有一本字典：fav_food = {'jen':'pizza','eric':'burrito','jason':'spaghetti','tom':'mac'}  然后有一个列表：users = ['jason', 'phil', 'jen', 'ben']  这里的场景是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")回报应该是：Jason likes Spaghetti  Phil hasn't taken the poll  Jen likes Pizza  Ben hasn't taken the poll  我想使用循环 'for' 并以某种方式通过字典迭代列表......但无论我做什么，我都会收到错误。如果可能的话，我更愿意以最“Python”的方式来做。

Answer 1

你可以试试这个

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")

这将输出为-

Jason likes Spaghetti

Phil hasn't taken the poll

Jen likes Pizza

Ben hasn't taken the poll

Answer 2

你的意思是喜欢

for user in users:

    try:

        print('{} likes {}'.format(user, fav_food[user]))

    except KeyError:

        print("{} hasn't taken the poll".format(user))

这将遍历所有用户，如果特定用户没有最喜欢的食物，那么它只会打印您所说的内容。

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")

像魅力一样工作，但值得记住的是，如果用户将空字符串作为他们最喜欢的食物，它会说他们没有参加投票