Python，如何合并 2 个 pandas DataFrame

Question

假设我有两个不同索引的 pandas Dataframe例如:

df1:

email                |       other_field
_________________________________________
email1@email.com     |           2
email2@email.com     |           1
email3@email.com     |           6

和 df2:

new_field
__________
    1
    7
    4

2 个数据帧具有相同的大小。我怎样才能合并它们两个以获得类似的输出？

df3:

email                |       other_field     |       new_field
________________________________________________________________
email1@email.com     |           2           |           1
email2@email.com     |           1           |           7
email3@email.com     |           6           |           4

我试过这个:

df3 = pd.merge(df1, df2, left_index=True, right_index=True)

但尽管 df1 和 df2 具有相同的大小，但 df3 具有较小的大小

Answer 1

在这种情况下你可以concat:

In [70]:

pd.concat([df1,df2],axis=1)

Out[70]:
              email  other_field  new_field
0  email1@email.com            2          1
1  email2@email.com            1          7
2  email3@email.com            6          4

如果需要，您可以选择传递 ignore_index=True。

join 也可以:

In [71]:

df1.join(df2)

Out[71]:
              email  other_field  new_field
0  email1@email.com            2          1
1  email2@email.com            1          7
2  email3@email.com            6          4

同样在索引匹配的情况下，直接赋值也可以:

In [72]:

df1['new_field'] = df2['new_field']
df1
Out[72]:
              email  other_field  new_field
0  email1@email.com            2          1
1  email2@email.com            1          7
2  email3@email.com            6          4