Python - 如果另一列具有列表中的值，则 Pandas 会替换列中的值

Question

我有数十万行看起来像这样(实际上有比这更多的数据，但我试图简化我一直在尝试的想法)......

index  status       location
0      infected     area5
1      healthy      area6
2      healthy      area3
3      infected     area8
4      healthy      area1
5      healthy      area8
6      healthy      area5
7      healthy      area2
8      healthy      area4
9      healthy      area10
10     ....          ....

我正在尝试根据某个区域是否被感染来更新 status 列。所以我基本上列出了感染区域:

infected_areas = ['area5', 'area8']

然后我要做的是查看所有行(或者实际上只是“健康”行)，如果其中任何行与我的 infected_areas 列表中的匹配，则将 status 更改为 infected。

所以对于我上面的例子，输出应该是这样的:

index  status       location
0      infected     area5
1      healthy      area6
2      healthy      area3
3      infected     area8
4      healthy      area1
5      infected     area8
6      infected     area5
7      healthy      area2
8      healthy      area4
9      healthy      area10
10     ....          ....

这是我一直在使用的，但还没有取得任何进展:

`df[df['location'].isin(location)]['status'] = 'infected'

Answer 1

只需使用.loc

df.loc[df.location.isin(infected_areas),'status']='infected'
df
Out[49]: 
   index    status location
0      0  infected    area5
1      1   healthy    area6
2      2   healthy    area3
3      3  infected    area8
4      4   healthy    area1
5      5  infected    area8
6      6  infected    area5
7      7   healthy    area2
8      8   healthy    area4
9      9   healthy   area10