Python中的Case条件

我试图在python中实现一个case条件

Sql等价物如下所示-

case when entered_by = created_by_user then entered_by
            when entered_by = entered_by then entered_by
            when modified_by = created_by_user then modified_by
            when modified_by = entered_by then modified_by
      end as "AD_ID" 

我已经编写了下面的pandas代码来实现上述功能，但是出现了一个错误-

def func(row):
    if dftemp['entered_by'] == dftemp['created_by_user']:
        return dftemp['entered_by']
    elif dftemp['entered_by'] == dftemp['entered_by']:
        return dftemp['entered_by']
    elif dftemp['modified_by'] == dftemp['created_by_user']:
        return dftemp['modified_by']
    elif dftemp['modified_by'] == dftemp['entered_by']:
        return dftemp['modified_by']    
    else:
        return 'other'

dftemp['AD_ID'] = dftemp.apply(func, axis=1)

我得到下面的错误-

ValueError: ('The truth value of a Series is ambiguous. Use a.empty, a.bool(), a.item(), a.any() or a.all().', u'occurred at index 0')

有没有更好的方法实现同样的目标

谢谢

@驴子孔-我尝试了下面的，没有工作-

def func(row):
    if assert_series_equal(dftemp['entered_by'], dftemp['created_by_user']):
        return dftemp['entered_by']
    elif assert_series_equal(dftemp['entered_by'], dftemp['entered_by']):
        return dftemp['entered_by']
    elif assert_series_equal(dftemp['modified_by'], dftemp['created_by_user']):
        return dftemp['modified_by']
    elif assert_series_equal(dftemp['modified_by'], dftemp['entered_by']):
        return dftemp['modified_by']    
    else:
        return 'other'

dftemp['AD_ID'] = dftemp.apply(func, axis=1) 

---

func将行作为参数，但不使用它。所有dftemp变量都应为row。此外，我认为这更干净：

def func(row):
    if assert_series_equal(row.entered_by in [row.created_by_user, row.entered_by]):
        return dftemp.entered_by
    if assert_series_equal(row.modified_by in [row.created_by_user, row.entered_by]):
        return dftemp.modified_by 
    return 'other'