如何从ID不存在的pandas数据框中查找记录? [英] How to find the records from a pandas dataframe which ID’s doesn’t exist?

问题描述

我有2个如下所示的pandas数据框. 我想合并它们，以便在第二个数据框中找到不存在的ID.

I got 2 pandas dataframes like below. I want to merge them so I can find the ID's in the second dataframe who doesn't exist.

+----+---------+
| ID |  Name   |
+----+---------+
|  1 | Henk    |
|  2 | Jon     |
|  3 | Sjord   |
|  4 | Bjorn   |
|  5 | Margita |
|  6 | Marry   |
|  7 | John    |
|  8 | Sam     |
|  9 | Hertog  |
+----+---------+

+-----+-----------+
| ID  | Feature_1 |
+-----+-----------+
|   1 | 1.1       |
|   1 | 2.2       |
|   2 | 4.4       |
|   2 | 100.10    |
|   4 | 0.1       |
|   4 | 13.2      |
|   7 | 18.2      |
|  82 | 19.21     |
| 100 | 992.21    |
+-----+-----------+

如何搜索第二组中不存在的ID，并将其放置在如下所示的另一个数据框中?

How can I search which ID in the second set doesn’t exist and place them in another dataframe like below?

+-----+-----------+
| ID  | Feature_1 |
+-----+-----------+
|  82 | 19.21     |
| 100 | 992.21    |
+-----+-----------+

推荐答案

使用isin

df2=df2[~df2.ID.isin(df1.ID)].copy()

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