捕获Pandas中第2和第3空格之前的所有字符串

Question

我理解如何从空格的第一次出现中分割字符串。我的问题是如何分割第二次第三次出现的空格，并捕获之前的所有字符串。

df = pd.DataFrame({"cid" : {0 : "cd1", 1 : "cd2", 2 : "cd3"},
                   "Name" : {0 : "John Maike Leiws", 1 : "Katie Sue Adam", 2 : "Tanaka Ubri Kse Suri"}}).set_index(['cid'])

                     Name
cid
cd1      John Maike Leiws
cd2        Katie Sue Adam
cd3  Tanaka Ubri Kse Suri

df['split_one'] = df.Name.str.split().str[0]

预期产出：

                     Name  split_one   split_two   split_three
cid
cd1      John Maike Leiws      John    John Maike  John Maike Leiws
cd2        Katie Sue Adam     Katie    Katie Sue   Katie Sue Adam
cd3  Tanaka Ubri Kse Suri    Tanaka    Tanaka Ubri Tanaka Ubri Kse

Answer 1

将索引与str一起使用，然后使用Series.str.join

s = df.Name.str.split()
df['split_one'] = s.str[0]
df['split_two'] = s.str[:2].str.join(' ')
df['split_three'] = s.str[:3].str.join(' ')
print (df)
                     Name split_one    split_two       split_three
cid                                                               
cd1      John Maike Leiws      John   John Maike  John Maike Leiws
cd2        Katie Sue Adam     Katie    Katie Sue    Katie Sue Adam
cd3  Tanaka Ubri Kse Suri    Tanaka  Tanaka Ubri   Tanaka Ubri Kse

Answer 2

使用regex的一种简单方法是使用嵌套捕获组：

df['Name'].str.extract('(((\S+)\s\S+)\s\S+)').iloc[:,::-1]

产出：

                    0            1       2
cid                                       
cd1  John Maike Leiws   John Maike    John
cd2    Katie Sue Adam    Katie Sue   Katie
cd3   Tanaka Ubri Kse  Tanaka Ubri  Tanaka

要补充的是，只需颠倒顺序：

df[['split_one', 'split_two', 'split_three']] = df['Name'].str.extract('(((\S+)\s\S+)\s\S+)').iloc[:,::-1]

产出：

                     Name split_one    split_two       split_three
cid                                                               
cd1      John Maike Leiws      John   John Maike  John Maike Leiws
cd2        Katie Sue Adam     Katie    Katie Sue    Katie Sue Adam
cd3  Tanaka Ubri Kse Suri    Tanaka  Tanaka Ubri   Tanaka Ubri Kse

Answer 3

我不知道你是在找普通的还是简单的东西。这是一种简单的方法。

 df = pd.DataFrame({"cid" : {0 : "cd1", 1 : "cd2", 2 : "cd3"},
                       "Name" : {0 : "John Maike Leiws", 1 : "Katie Sue Adam", 2 : "Tanaka Ubri Kse Suri"}}).set_index(['cid'])
    
    s = df.Name.str.split().str
    df['split_one'] = s[0]
    df['split_two'] = s[0] + ' ' + s[1]
    df['split_three'] = s[0] + ' ' + s[1] + ' ' + s[2]