按特定列值對數據框進行分組

Jeppi 发表于 Dev

傑皮

我有一個包含很多列的熊貓數據框。我想創建一個只有兩列的新數據框。第一列應包含出現在原始數據框特定列中的所有值。第二列應包含與第一列的值匹配的原始數據框的所有其他數據。

例如，我的輸入數據框的結構如下：

    Name            Menu                City
0   Foo Burgers     Burgers and Fries   New York
1   Cheesy's        Cheeseburgers       New York
2   Buggy Burgers   Insect Burgers      London
3   Fry Guy         Fries               London
4   Beermania       Beer                Berlin

在代碼中：

df = pd.DataFrame([["Foo Burgers", "Burgers and Fries", "New York"], 
                   ["Cheesy's", "Cheeseburgers", "New York"],
                   ["Buggy Burgers", "Insect Burgers", "London"],
                   ["Fry Guy", "Fries", "London"],
                   ["Beermania", "Beer", "Munich"]], columns=["Name","Menu","City"])

如何輕鬆地將數據框轉換為以下目標結構？

    City        Restaurants
0   New York    [{"Name": "Foo Burgers", "Menu": "Burgers and Fries"}, {"Name":"Cheesy's", "Menu": "Cheeseburgers"}]
1   London      [{"Name": "Buggy Burgers", "Menu": "Insect Burgers"}, {"Name":"Fry Guy", "Menu": "Fries"}]
2   Munich      [{'Name': 'Beermania', 'Menu': 'Beer'}]

在代碼中：

goal_df = pd.DataFrame([["New York", [{"Name": "Foo Burgers", "Menu": "Burgers and Fries"}, {"Name":"Cheesy's", "Menu": "Cheeseburgers"}], ],
                        ["London", [{"Name": "Buggy Burgers", "Menu": "Insect Burgers"}, {"Name":"Fry Guy", "Menu": "Fries"}], ],
                        ["Munich", [{"Name": "Beermania", "Menu": "Beer"}], ]], columns=["City", "Restaurants"])

廣黃

你可以做一個groupby().agg有to_dict：

(df.drop('City', axis=1).groupby(df['City'])
   .apply(lambda x: x.to_dict(orient='records'))
   .reset_index(name='Restaurants')
)

輸出：

       City                                        Restaurants
0    London  [{'Name': 'Buggy Burgers', 'Menu': 'Insect Bur...
1    Munich            [{'Name': 'Beermania', 'Menu': 'Beer'}]
2  New York  [{'Name': 'Foo Burgers', 'Menu': 'Burgers and ...

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