pandas 根据多种条件过滤行

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问题描述

我使用pandas 0.13.1 Python 2.7:

I use pandas 0.13.1 Python 2.7:

我在risk列中有一些值，都不是Small，Medium或High.我想删除值不为Small，Medium和High的行.我尝试了以下方法:

I have some values in the risk column that are neither, Small, Medium or High. I want to delete the rows with the value not being Small, Medium and High. I tried the following:

df = df[(df.risk == "Small") | (df.risk == "Medium") | (df.risk == "High")]

但是这将返回一个空的数据帧.如何正确过滤它们?

But this returns an empty data frame. How can I filter them correctly?

推荐答案

我认为您想要:

df = df[(df.risk.isin(["Small","Medium","High"]))]

示例:

In [5]:
import pandas as pd
df = pd.DataFrame({'risk':['Small','High','Medium','Negligible', 'Very High']})
df

Out[5]:

         risk
0       Small
1        High
2      Medium
3  Negligible
4   Very High

[5 rows x 1 columns]

In [6]:

df[df.risk.isin(['Small','Medium','High'])]

Out[6]:

     risk
0   Small
1    High
2  Medium

[3 rows x 1 columns]

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