python – 仅替换数据框中列的第一个字符

我试图替换数据帧中每行语句的第一个出现的某些单词.然而,传递’1’位置正在取代一切.为什么传递’1’代替不起作用？这有不同的方式吗？
谢谢！

初始：

df_test = pd.read_excel('sample.xlsx')
print('Initial: \n',df_test)

Initial: 
                                         some_text
0   ur goal is to finish shopping for books today
1  Our goal is to finish shopping for books today
2                          The help is on the way
3        he way is clear … he is going to library

尝试：

df_test['some_text'] = df_test['some_text'] \
        .str.replace('ur ','Our ',1) \
        .str.replace('he ','The ',1) 
print('Tried:\n',df_test)

Tried: (Incorrect Results) 
                                          some_text
0   Our goal is to finish shopping for books today
1  OOur goal is to finish shopping for books today
2                          TThe help is on the way
3        The way is clear … he is going to library

需要最终输出：

                                    some_text
0   Our goal is to finish shopping for books today
1  Our goal is to finish shopping for books today
2                          The help is on the way
3        The way is clear … he is going to library

解决方法:

编程语言,包括Python,不像人类那样阅读.你需要告诉Python按空格分割.例如,通过str.split：

df = pd.DataFrame({'some_text': ['ur goal is to finish shopping for books today',
                                 'Our goal is to finish shopping for books today',
                                 'The help is on the way',
                                 'he way is clear … he is going to library']})

d = {'ur': 'Our', 'he': 'The'}

df['result'] = [' '.join((d.get(i, i), j)) for i, j in df['some_text'].str.split(n=1)]

print(df)

                                        some_text  \
0   ur goal is to finish shopping for books today   
1  Our goal is to finish shopping for books today   
2                          The help is on the way   
3        he way is clear … he is going to library   

                                           result  
0  Our goal is to finish shopping for books today  
1  Our goal is to finish shopping for books today  
2                          The help is on the way  
3       The way is clear … he is going to library