如何在 Pandas DataFrame 中对列进行分组（忽略顺序）？

Question

我有一个 pandas 数据框（8 列中的 4 列）：

df = pd.DataFrame( {"departure_country":["Mexico","Mexico","United States","United States","United States","United States","Japan","United States","United States","United States"],"departure_city":["Guadalajara","Guadalajara","New York","Chicago","Los Angeles","Michigan","Tokyo","New York","New York","Chicago"],"destination_country":["United States","United States","United States","United States","Mexico","United States","United States","Mexico","United States","Japan"],"destination_city":["Los Angeles","Los Angeles","Chicago","New York","Guadalajara","New York","Chicago","Guadalajara","Michigan","Tokyo"]})

df
    departure_country   departure_city  destination_country destination_city
0   Mexico              Guadalajara     United States       Los Angeles
1   Mexico              Guadalajara     United States       Los Angeles
2   United States       New York        United States       Chicago
3   United States       Chicago         United States       New York
4   United States       Los Angeles     Mexico              Guadalajara
5   United States       Michigan        United States       New York
6   Japan               Tokyo           United States       Chicago
7   United States       New York        Mexico              Guadalajara
8   United States       New York        United States       Michigan
9   United States       Chicago         Japan               Tokyo

我想分析每个组中的数据，所以我想先按出发地和目的地的“同一对”进行分组，例如：

    departure_country   departure_city  destination_country destination_city
0   Mexico              Guadalajara     United States       Los Angeles
1   Mexico              Guadalajara     United States       Los Angeles
2   United States       Los Angeles     Mexico              Guadalajara
3   United States       New York        United States       Chicago
4   United States       Chicago         United States       New York
5   United States       Michigan        United States       New York
6   United States       New York        United States       Michigan
7   Japan               Tokyo           United States       Chicago
8   United States       Chicago         Japan               Tokyo
9   United States       New York        Mexico              Guadalajara

是否可以在 DataFrame 中制作它？我尝试过 groupby 和 key-value，但我失败了。 非常感谢您的帮助，谢谢！

Answer 1

我相信有人会想到一个更好的优化解决方案，但一种方法是创建您的国家/城市对的排序元组并按它排序：

print (df.assign(country=[tuple(sorted(i)) for i in df.filter(like="country").to_numpy()],
                 city=[tuple(sorted(i)) for i in df.filter(like="city").to_numpy()])
         .sort_values(["country","city"], ascending=False).filter(like="_"))

  departure_country departure_city destination_country destination_city
5     United States       Michigan       United States         New York
8     United States       New York       United States         Michigan
2     United States       New York       United States          Chicago
3     United States        Chicago       United States         New York
7     United States       New York              Mexico      Guadalajara
0            Mexico    Guadalajara       United States      Los Angeles
1            Mexico    Guadalajara       United States      Los Angeles
4     United States    Los Angeles              Mexico      Guadalajara
6             Japan          Tokyo       United States          Chicago
9     United States        Chicago               Japan            Tokyo