Python Pandas Dataframe：将列拆分为多列，右对齐不一致的单元格条目
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Pandas Dataframe: split column into multiple columns, right-align inconsistent cell entries
提问by jamesbev
I have a pandas dataframe with a column named 'City, State, Country'. I want to separate this column into three new columns, 'City, 'State' and 'Country'.
我有一个 Pandas 数据框，其中有一列名为“城市、州、国家”。我想将此列分成三个新列，“城市”、“州”和“国家”。
0 HUN
1 ESP
2 GBR
3 ESP
4 FRA
5 ID, USA
6 GA, USA
7 Hoboken, NJ, USA
8 NJ, USA
9 AUS
Splitting the column into three columns is trivial enough:
将列拆分为三列非常简单：
location_df = df['City, State, Country'].apply(lambda x: pd.Series(x.split(',')))
However, this creates left-aligned data:
但是，这会创建左对齐的数据：
0 1 2
0 HUN NaN NaN
1 ESP NaN NaN
2 GBR NaN NaN
3 ESP NaN NaN
4 FRA NaN NaN
5 ID USA NaN
6 GA USA NaN
7 Hoboken NJ USA
8 NJ USA NaN
9 AUS NaN NaN
How would one go about creating the new columns with the data right-aligned? Would I need to iterate through every row, count the number of commas and handle the contents individually?
如何创建数据右对齐的新列？我是否需要遍历每一行，计算逗号的数量并单独处理内容？
采纳答案by Karl D.
I'd do something like the following:
我会做类似以下的事情：
foo = lambda x: pd.Series([i for i in reversed(x.split(','))])
rev = df['City, State, Country'].apply(foo)
print rev
0 1 2
0 HUN NaN NaN
1 ESP NaN NaN
2 GBR NaN NaN
3 ESP NaN NaN
4 FRA NaN NaN
5 USA ID NaN
6 USA GA NaN
7 USA NJ Hoboken
8 USA NJ NaN
9 AUS NaN NaN
I think that gets you what you want but if you also want to pretty things up and get a City, State, Country column order, you could add the following:
我认为这可以满足您的需求，但如果您还想美化并获得 City、State、Country 列顺序，您可以添加以下内容：
rev.rename(columns={0:'Country',1:'State',2:'City'},inplace=True)
rev = rev[['City','State','Country']]
print rev
City State Country
0 NaN NaN HUN
1 NaN NaN ESP
2 NaN NaN GBR
3 NaN NaN ESP
4 NaN NaN FRA
5 NaN ID USA
6 NaN GA USA
7 Hoboken NJ USA
8 NaN NJ USA
9 NaN NaN AUS
回答by Naufal
Since you are dealing with strings I would suggest the amendment to your current code i.e.
由于您正在处理字符串，我建议修改您当前的代码，即
location_df = df[['City, State, Country']].apply(lambda x: pd.Series(str(x).split(',')))
I got mine to work by testing one of the columns but give this one a try.
我通过测试其中一列让我的工作正常工作，但请尝试一下。
回答by Dolittle Wang
Assume you have the column name as target
假设您将列名作为目标
df[["City", "State", "Country"]] = df["target"].str.split(pat=",", expand=True)
