Python 3.x Pandas groupby：仅对部分记录进行聚合

我有以下数据框：

id   src     target     duration
001     A      C           4
001     B      C           3
001     C      C           2
002     B      D           5
002     C      D           2

我用下面的代码做了一些聚合，效果很好

df_new = df.groupby(['id','target']) \
        .apply(lambda x: pd.Series({'min_duration': min(x['duration']), \
                                    'total_duration':sum(x['duration']), \
                                    'all_src':list(x['src'])
                                   })).reset_index()

现在我只想计算

src！=目标

记录。我修改了我的代码，如下所示：

df_new = df.groupby(['id','target']) \
        .apply(lambda x: pd.Series({'min_duration': min(x['duration']), \
                                    'total_duration':sum(x['duration']), \
                                    'total_duration_condition':sum(x['duration']) if x['src'] != x['target'], \
                                    'all_src':list(x['src'])
                                   })).reset_index()

但是在我的新行中出现了

无效语法
错误：

'total_duration_condition':sum(x['duration']) if x['src'] != x['target']

我想知道什么才是只对部分记录求和的正确方法？谢谢
 试着像下面这样编写代码

df.groupby(['id','target']).apply(lambda x: pd.Series({'min_duration': min(x['duration']), \
                                    'total_duration':sum(x['duration']), \
                                    'total_duration_condition':sum(x['duration'][x['src'] != x['target']]), \# I change this part
                                    'all_src':list(x['src'])
                                   })).reset_index()

换乘线路

'total_duration_condition':sum(x['duration']) if x['src'] != x['target']

到

试着像下面这样编写代码

df.groupby(['id','target']).apply(lambda x: pd.Series({'min_duration': min(x['duration']), \
                                    'total_duration':sum(x['duration']), \
                                    'total_duration_condition':sum(x['duration'][x['src'] != x['target']]), \# I change this part
                                    'all_src':list(x['src'])
                                   })).reset_index()

换乘线路

'total_duration_condition':sum(x['duration']) if x['src'] != x['target']

到