Python 用条件填充柱

我有一个包含两列的数据框：

          Col1          Col2
1          NaN         Someval1
2           Y          Someval2
3           N          Someval3
4          NaN           NaN
5          NaN         Someval4

我想向NaN提供以下条件：

If Col1 has NaN and Col2 has a Someval1 that is in list 1 then fillna with Y
If Col1 has NaN and Col2 has a Someval4 that is in list 2 then fillna with N
If Col1 has NaN and Col2 has a NaN that is in list 2 then fillna with N

有什么建议吗？（不知道是否可能）

非常感谢

我认为您需要以下条件和条件：

另一个解决方案包括：

---

另一种解决方案具有一个条件和

fillna

：

L1 = ['Someval1','Someval8']
L2 = ['Someval4','Someval9', np.nan]

df['Col1'] = df['Col1'].mask(df['Col2'].isin(L1), df['Col1'].fillna('Y'))
df['Col1'] = df['Col1'].mask(df['Col2'].isin(L2), df['Col1'].fillna('N'))
print (df)
  Col1      Col2
1    Y  Someval1
2    Y  Someval2
3    N  Someval3
4    N       NaN
5    N  Someval4

这是解决办法

完整脚本：

df = pd.read_csv(StringIO("""Col1          Col2
1          NaN         Someval1
2           Y          Someval2
3           N          Someval3
4          NaN           NaN
5          NaN         Someval4
"""), sep="\s+")

df.loc[df.Col1.isnull() & df.Col2.isin(['Someval1']), 'Col1'] = 'Y'
df.loc[df.Col1.isnull() & df.Col2.isin(['Someval4']), 'Col1'] = 'N'
df.loc[df.Col1.isnull() & df.Col2.isin([np.nan]), :] = 'N'

df

  Col1      Col2
1    Y  Someval1
2    Y  Someval2
3    N  Someval3
4    N         N
5    N  Someval4

你可以用

df.Col1[(df['Col1'].isnull())&(df['Col2']=='Someval1')] = 'Y'
df.Col1[(df['Col1'].isnull())&(df['Col2']=='Someval4')] = 'N'
df.Col1[(df['Col1'].isnull())&(df['Col2'].isnull())] = 'N'

---

列表1中的NaN？：）清单2，感谢验证，我将编辑第5行的第二行“Someval4”；第二行和第三行不支持第四行和第五行中的fillna到Col1rows@tworec我认为

列表2

指的是

列2

，我将对其进行更改。

df.loc[df.Col1.isnull() & df.Col2.isin(['Someval1']), 'Col1'] = 'Y'
df.loc[df.Col1.isnull() & df.Col2.isin(['Someval4']), 'Col1'] = 'N'
df.loc[df.Col1.isnull() & df.Col2.isin([np.nan]), :] = 'N'

df = pd.read_csv(StringIO("""Col1          Col2
1          NaN         Someval1
2           Y          Someval2
3           N          Someval3
4          NaN           NaN
5          NaN         Someval4
"""), sep="\s+")

df.loc[df.Col1.isnull() & df.Col2.isin(['Someval1']), 'Col1'] = 'Y'
df.loc[df.Col1.isnull() & df.Col2.isin(['Someval4']), 'Col1'] = 'N'
df.loc[df.Col1.isnull() & df.Col2.isin([np.nan]), :] = 'N'

df

  Col1      Col2
1    Y  Someval1
2    Y  Someval2
3    N  Someval3
4    N         N
5    N  Someval4

df.Col1[(df['Col1'].isnull())&(df['Col2']=='Someval1')] = 'Y'
df.Col1[(df['Col1'].isnull())&(df['Col2']=='Someval4')] = 'N'
df.Col1[(df['Col1'].isnull())&(df['Col2'].isnull())] = 'N'