熊猫，放下空柱子

Question

如何检查是否有一列只填充了"None"值？如何删除该列？

所以类似于：

If column in dataframe is None:
drop column

下面是一个伪数据示例，解决方案应该将第5列标识为空，并删除该列：

import pandas as pd
import numpy as np
# dictionary of lists
dict = {'First Score':[100, np.nan, np.nan, 95],
'Second Score': [30, np.nan, 45, 56],
'Third Score':[52, np.nan, 80, 98],
'Fourth Score':[60, 67, 68, 65],
'Fifth Score':[ np.nan,  np.nan,  np.nan,  np.nan]
}
# creating a dataframe from dictionary
df = pd.DataFrame(dict)
df = df.where(pd.notnull(df), None)

Answer 1

试试这个：

df_out = df.dropna(how='all', axis=1)

输出：

First Score Second Score Third Score  Fourth Score
0       100.0         30.0        52.0            60
1        None         None        None            67
2        None         45.0        80.0            68
3        95.0         56.0        98.0            65

根据文档，pd.DataFrame.dropna有参数"how"，我们可以将其设置为"all"。