python - Python 中的双 IIF 语句

Question

我有一个 SQL 代码，其中有两个 IIF 语句，也就是说，if true 部分是另一个 IIF 语句，我正在尝试使用 np.where 在 python 中重新创建它

SQL 代码是:

IIF ([STATE] Is Null, IIF ([COUNTRY] Is Null,'No Country',[COUNTRY]), [STATE])

我已经尝试过这个:

DF['NewCol'] = np.where(DF['STATE'].isnull(),(np.where(DF['COUNTRY'].isnull(),'No Country','DF['COUNTRY']'),DF['STATE']))

感谢任何帮助

Answer 1

我认为你需要:

DF['NewCol'] = np.where(DF['STATE'].isnull(),
               np.where(DF['COUNTRY'].isnull(),'No Country', DF['COUNTRY']),DF['STATE'])

示例:

DF = pd.DataFrame({'STATE':[np.nan,'a','b',np.nan],
                   'COUNTRY':[np.nan,'c',np.nan, 'd']})

print (DF)
  COUNTRY STATE
0     NaN   NaN
1       c     a
2     NaN     b
3       d   NaN

DF['NewCol'] = np.where(DF['STATE'].isnull(),
               np.where(DF['COUNTRY'].isnull(),'No Country', DF['COUNTRY']),DF['STATE'])

print (DF)
  COUNTRY STATE      NewCol
0     NaN   NaN  No Country
1       c     a           a
2     NaN     b           b
3       d   NaN           d

如果需要首先在 COUNTRY 列的输出列值中:

DF['NewCol'] = np.where(DF['COUNTRY'].isnull(),
               np.where(DF['STATE'].isnull(),'No Country', DF['STATE']),DF['COUNTRY'])

print (DF)
  COUNTRY STATE      NewCol
0     NaN   NaN  No Country
1       c     a           c
2     NaN     b           b
3       d   NaN           d