拆分 pandas 列并将最后一个元素添加到新列

问题描述

我有一个包含(除了其他列)全名的熊猫数据框:

I have a pandas dataframe containing (besides other columns) full names:

 fullname
 martin master
 andreas test

我想创建一个新列，它沿空白区域拆分全名列，并将最后一个元素分配给新列.结果应如下所示:

I want to create a new column which splits the fullname column along the blank space and assigns the last element to a new column. The result should look like:

 fullname           lastname
 martin master      master
 andreas test       test

我认为它会像这样工作:

I thought it would work like this:

df['lastname'] = df['fullname'].str.split(' ')[-1]

但是，我得到一个 KeyError: -1

我使用 [-1]，这是拆分组的最后一个元素，以确保我得到真实的姓氏.在某些情况下(例如像 andreas martin master 这样的名字)，这有助于获得姓氏，即 master.

I use [-1], that is the last element of the split group, in order to be sure that I get the real last name. In some cases (e.g. a name like andreas martin master), this helps to get the last name, that is, master.

那我该怎么做呢?

推荐答案

您需要另一个 str 来访问每一行的最后一个拆分，您所做的实际上是尝试使用非-存在的标签:

You need another str to access the last splits for every row, what you did was essentially try to index the series using a non-existent label:

In [31]:

df['lastname'] = df['fullname'].str.split().str[-1]
df
Out[31]:
         fullname lastname
0   martin master   master
1    andreas test     test

这篇关于拆分 pandas 列并将最后一个元素添加到新列的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持！