Question

我有一个这样的数据框：

import numpy as np
import pandas as pd

df = pd.DataFrame({'carrier': ['c1','c1','c1','c2','c2','c2','c3','c4','c5','c5'],
                   'airport': ['a1','a3','a1','a1','a2','a2','a3','a4','a4','a1'],
                  })

df

  carrier airport  
0      c1      a1  
1      c1      a3  
2      c1      a1  
3      c2      a1  
4      c2      a2  
5      c2      a2  
6      c3      a3  
7      c4      a4  
8      c5      a4  
9      c5      a1

我想找到服务于机场的承运人的数量，以便至少有2个不同的承运人为机场提供服务。

该怎么做？

必填输出：

airport carrier n_carrier
a1  c1  3  # airport a1 is served by 3 distinct carriers
a3  c1  2  # airport a3 is served by 2 distinct carriers
a1  c2  3  # NOTE: here we do not see a2 because it has only
a3  c3  2  #       one carrier, so it is excluded
a4  c4  2
a4  c5  2  # airport a4 is served by 2 distinct carriers
a1  c5  3

Answer 1

update := bson.M{
    "$set": bson.M{
        "name": obj.Name,
    },
    "$addToSet": bson.M{"activities": bson.M{"$each": obj.Activities }},
}
cursor, err := collection.UpdateOne(context.Background(), filter, update )

这应该给您您想要的东西。按唯一性数量转换分组依据，然后仅查看大于1的内容，然后删除重复项

熊猫：如何查找来自另一列的一列的唯一元素数量？

1 个答案: