Question

我有两个数据框：

DF1

            GOOG AAPL XOM  IBM  Cash
Date                               
2009-01-14  NaN  150  NaN  NaN  NaN
2009-01-21  NaN  -150 NaN  400  NaN

DF2

           GOOG AAPL  XOM  IBM Cash
Date                               
2009-01-14  NaN  100  NaN  NaN  NaN
2009-01-21  NaN  30   NaN  15   NaN

如何将它们相乘，以便创建一个新的DF，如下所示：我基本上是在尝试DF1，看看DF2中是否存在索引和列，如果存在，请将它们相乘。

重要的是要注意DF1和DF2的索引可能不完全相同。因此，答案必须考虑到这一点。

           GOOG AAPL   XOM  IBM Cash
Date                               
2009-01-14  NaN  15000 NaN  NaN  NaN
2009-01-21  NaN  -4500 NaN  6000 NaN

Answer 1

使用concat和groupby.prod：

df = pd.concat([df1,df2])
df.groupby(df.index).prod(min_count=1)
            GOOG   AAPL  XOM     IBM  Cash
Date                                      
2009-01-14   NaN  15000  NaN     NaN   NaN
2009-01-21   NaN  -4500  NaN  6000.0   NaN

Answer 2

使用DataFrame.mul应该处理索引：

SELECT s1.`group` AS groupId1,  (
    SELECT id
    FROM `students` s2
    WHERE s2.`group` = s1.`group`
    ORDER BY s2.grade DESC, s2.id ASC
    LIMIT 0,1
 ) AS bestGradeId,  (
    SELECT id
    FROM `students` s2
    WHERE s2.`group` = s1.`group`
    ORDER BY s2.grade DESC, s2.id ASC
    LIMIT 1,1
 ) AS best2GradeId,  (
    SELECT id
    FROM `students` s2
    WHERE s2.`group` = s1.`group`
    ORDER BY s2.grade DESC, s2.id ASC
    LIMIT 2,1
 ) AS best3GradeId
FROM `students` s1
GROUP BY s1.`group`

如何根据行索引和列名在两个数据框之间使用多个值？

2 个答案: