如何使用熊猫拆分数据帧?

Question

>我有以下数据帧要处理， 东风

Name                City
Hat, Richards       Paris
Adams               New york
Tim, Mathews        Sanfrancisco
chris, Moya De      Las Vegas
kate, Moris         Atlanta
Grisham HA          Middleton
James, Tom, greval  Rome

我预期的数据帧应该如下，DF

Name         Last_name           City
Hat          Richards            Paris
Adams               New york
Tim          Mathews             Sanfrancisco
chris        Moya De             Las Vegas
kate         Moris               Atlanta
Grisham HA          Middleton
James, Tom   greval              Rome

拆分应在最后一个"，"上完成，如果没有"，"，则整个其他单词或短语应位于"Last_name"列中，而"名称"列应保持空置。

Answer 1

将str.split与radd一起使用以添加,，最后str.lstrip：

df[['first','last']] = df['Name'].radd(', ').str.rsplit(', ', n=1, expand=True)
df['first'] = df['first'].str.lstrip(', ')
print (df)
Name          City       first        last
0       Hat, Richards         Paris         Hat    Richards
1               Adams      New york                   Adams
2        Tim, Mathews  Sanfrancisco         Tim     Mathews
3      chris, Moya De     Las Vegas       chris     Moya De
4         kate, Moris       Atlanta        kate       Moris
5          Grisham HA     Middleton              Grisham HA
6  James, Tom, greval          Rome  James, Tom      greval

Answer 2

将str.split与n=-1一起使用(这是默认的，您可以更改所需的内容(

newdf=df.Name.str.split(', ',expand=True,n=1).ffill(1)
newdf.loc[newdf[0]==newdf[1],0]=''
newdf
Out[923]: 
0          1
0    Hat   Richards
1             Adams
2    Tim    Mathews
3  chris     MoyaDe
4   kate      Moris
5         GrishamHA
df[['Name','LastName']]=newdf
df
Out[925]: 
Name          City   LastName
0    Hat         Paris   Richards
1              Newyork      Adams
2    Tim  Sanfrancisco    Mathews
3  chris      LasVegas     MoyaDe
4   kate       Atlanta      Moris
5            Middleton  GrishamHA

Answer 3

快速和肮脏

将pandas.str.split与str[::-1]一起使用以反转顺序

df[['Last_name', 'Name']] = df.Name.str.split(', ').str[::-1].apply(pd.Series)
df
Name          City   Last_name
0    Hat         Paris    Richards
1    NaN      New york       Adams
2    Tim  Sanfrancisco     Mathews
3  chris     Las Vegas     Moya De
4   kate       Atlanta       Moris
5    NaN     Middleton  Grisham HA