Question

如何检查某个值是否在嵌套的python词典中？

我想检查用户输入的选项是否在字典中，如果没有将新电影添加到字典中，如果要说明电影是否已存储。

我还希望用户输入电影选择和字典来打印该特定电影的详细信息，而不是全部10个。

点击链接查看代码图片。

这是书面代码：

topMovies = {1:{'Movie':'Avatar', 'Year': '2009', 'Gross Profit': '£2.788 billion', 'Budget': '£237 million'},
2:{'Movie':'Titanic', 'Year': '1997', 'Gross Profit': '£2.187 billion', 'Budget': '£200 million'},
3:{'Movie':'Star Wars: The Force Awakens', 'Year': '2015', 'Gross Profit': '£2.068 billion', 'Budget': '£306 million'},
4:{'Movie':'Avengers: Infinity War', 'Year': '2018', 'Gross Profit': '£1.814 billion', 'Budget': '£400 million'},
5:{'Movie':'Jurassic World', 'Year': '2015', 'Gross Profit': '£1.672 billion', 'Budget': '£150 million'},
6:{'Movie':'The Avengers', 'Year': '2012', 'Gross Profit': '£1.519 billion', 'Budget': '£220 million'},
7:{'Movie':'Fast and Furious 7', 'Year': '2015', 'Gross Profit': '£1.516 billion', 'Budget': '£190 million'},
8:{'Movie':'Avengers: Age of Ultron', 'Year': '2015', 'Gross Profit': '£1.405 billion', 'Budget': '£444 million'},
9:{'Movie':'Black Panther', 'Year': '2018', 'Gross Profit': '£1.344 billion', 'Budget': '£210 million'},
10:{'Movie':'Harry Potter and the Deathly Hollows: Part 2', 'Year': '2011', 'Gross Profit': '£1.342 billion', 'Budget': '£250 million (shared with part 1)'}}

for movieID, movieInfo in topMovies.items():
    print("\nNumber: ", movieID)
    for key in movieInfo:
        print(key , ": " , movieInfo[key])
print("\n")

#checking if movie already stored and if not add new movie else movie is already stored
choice = input('Please enter choice: ')
for x in topMovies:
    if choice != topMovies[x]:
        print("Enter new movie!")
        topMovies[x] = {}
        topMovies[x]['Movie'] = choice
        topMovies[x]['Year'] = input('Enter the year of release for the movie: ')
        topMovies[x]['Gross Profit'] = input('Enter the gross profit of the movie: ')
        topMovies[x]['budget'] = input('Enter the budget for the movie: ')
        print("\n")
        print(topMovies[x])
    elif choice == topMovies[x]['Movie']:
        print("Movie already stored!")
    break

Answer 1

在允许用户创建新条目之前，您必须针对所有电影choice值测试'Movie'的值：

choice = input('Please enter choice: ') for movie in topMovies.values(): if movie["Movie"] == choice: print("Movie already stored!") break else: # IMPORTANT: this is a 'else' for the `for` loop, # it will only be executed if the loop terminates # without a `break` # create the movie here - warning: you'll need to find # the highest `topMovies` key to compute the new movie key.

请注意，此解决方案效率低（顺序扫描为O（N）），并且不具备可读性。您可以通过使用更好的数据结构来改进它 - 当您看到一个dict，其键是连续的升序整数时，您可能需要list - 而反向索引（将电影名称映射到列表中的索引的dict）

top_movies = [ {'Movie':'Avatar', 'Year': '2009', 'Gross Profit': '£2.788 billion', 'Budget': '£237 million'}, {'Movie':'Titanic', 'Year': '1997', 'Gross Profit': '£2.187 billion', 'Budget': '£200 million'}, {'Movie':'Star Wars: The Force Awakens', 'Year': '2015', 'Gross Profit': '£2.068 billion', 'Budget': '£306 million'}, {'Movie':'Avengers: Infinity War', 'Year': '2018', 'Gross Profit': '£1.814 billion', 'Budget': '£400 million'}, {'Movie':'Jurassic World', 'Year': '2015', 'Gross Profit': '£1.672 billion', 'Budget': '£150 million'}, {'Movie':'The Avengers', 'Year': '2012', 'Gross Profit': '£1.519 billion', 'Budget': '£220 million'}, {'Movie':'Fast and Furious 7', 'Year': '2015', 'Gross Profit': '£1.516 billion', 'Budget': '£190 million'}, {'Movie':'Avengers: Age of Ultron', 'Year': '2015', 'Gross Profit': '£1.405 billion', 'Budget': '£444 million'}, {'Movie':'Black Panther', 'Year': '2018', 'Gross Profit': '£1.344 billion', 'Budget': '£210 million'}, {'Movie':'Harry Potter and the Deathly Hollows: Part 2', 'Year': '2011', 'Gross Profit': '£1.342 billion', 'Budget': '£250 million (shared with part 1)'} ] movies_index = {movie["Movie"].lower(): index for index, movie in enumerate(top_movies)} # .... choice = input('Please enter choice: ').strip() # dict lookup is O(1) and highly optimised if choice.lower() in movies_index: print("Movie already stored!") else: new_movie = {"Movie": choice} # fill in the fields # ... top_movies.append(new_movie) movies_index[choice.lower()] = len(top_movies) - 1

Answer 2

编辑2：这在你的例子中不起作用。让它留下来作为一个例子，而不是阅读整个问题＆＃34;

如果你正在寻找效率，那会有用吗：

choice = input("Movie name please: ...")
if {"Movie":choice} not in topMovies.values():
    etc etc etc

编辑：完整的例子，因为上面没有开箱即用而不适合你的代码......

topMovies={}
topMovies["1"]={"Movie":"Avatar"}
choice = input("Movie name please: ...")
if {"Movie":choice} not in topMovies.values():
    X=input("Rank: ")
    topMovies[X]={}
    topMovies[X][choice]=choice

如何检查值是否在嵌套的python字典中？

2 个答案: