python - 如何从 csv 数据添加数据框列

Question

我有 csv 数据

index   username
1       ailee
2       yura
3       sony
4       lily
5       alex
6       eunji
7       hyun
8       jingo
9       kim
10      min

集群的数据帧结果:

index   cluster
1        1
3        1
5        1
7        1
8        1
9        2
4        2
2        2
10       2
6        2

是否可以根据 csv 数据在 pd.dataframe 中添加用户名列？

Answer 1

我为此使用“DataFrame.merge”。这是代码

>>> import StringIO as sio
>>> import pandas as pd

>>> s1='''index   username
1       ailee
2       yura
3       sony
4       lily
5       alex
6       eunji
7       hyun
8       jingo
9       kim
10      min'''
>>> s2 = '''index   cluster
1        1
3        1
5        1
7        1
8        1
9        2
4        2
2        2
10       2
6        2'''

>>> df1=pd.read_csv(sio.StringIO(s1), index_col=0, delim_whitespace=True)
>>> df2=pd.read_csv(sio.StringIO(s2), index_col=0, delim_whitespace=True)

>>> df1
      username
index
1        ailee
2         yura
3         sony
4         lily
5         alex
6        eunji
7         hyun
8        jingo
9          kim
10         min
>>> df2
       cluster
index
1            1
3            1
5            1
7            1
8            1
9            2
4            2
2            2
10           2
6            2

>>> df1.merge(df2, left_index=True, right_index=True)
      username  cluster
index
1        ailee        1
3         sony        1
5         alex        1
7         hyun        1
8        jingo        1
9          kim        2
4         lily        2
2         yura        2
10         min        2
6        eunji        2