Python 如何在特定列中选择带有 NaN 的行？
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时间：2020-08-19 23:25:37 来源:igfitidea点击:
How to select rows with NaN in particular column?
提问by Dinosaurius
Given this dataframe, how to select only those rows that have "Col2" equal to NaN?
给定这个数据框，如何只选择那些“Col2”等于的行NaN？
In [56]: df = pd.DataFrame([range(3), [0, np.NaN, 0], [0, 0, np.NaN], range(3), range(3)], columns=["Col1", "Col2", "Col3"])
In [57]: df
Out[57]:
0 1 2
0 0 1 2
1 0 NaN 0
2 0 0 NaN
3 0 1 2
4 0 1 2
The result should be this one:
结果应该是这样的：
Out[57]:
0 1 2
1 0 NaN 0
回答by qbzenker
Try the following:
请尝试以下操作：
df[df['Col2'].isnull()]
回答by MaxU
@qbzenker provided the most idiomatic method IMO
@qbzenker 提供了最惯用的方法 IMO
Here are a few alternatives:
这里有一些替代方案：
In [28]: df.query('Col2 != Col2') # Using the fact that: np.nan != np.nan
Out[28]:
Col1 Col2 Col3
1 0 NaN 0.0
In [29]: df[np.isnan(df.Col2)]
Out[29]:
Col1 Col2 Col3
1 0 NaN 0.0
