python 怎么打印Pandas的Groupby对象？

如果直接打印grouby的结果默认是一个对象格式：

print(df.groupby('A'))
<pandas.core.groupby.DataFrameGroupBy object at 0x05416E90>

国外找到如下资料¹：

In Jupyter Notebook, if you do the following, it prints a nice grouped version of the object. The apply method helps in creation of a multiindex dataframe.

by = 'A'  # groupby 'by' argument
df.groupby(by).apply(lambda a: a[:])

Output:

             A  B
A                
one   0    one  0
      1    one  1
      5    one  5
three 3  three  3
      4  three  4
two   2    two  2

If you want the by column(s) to not appear in the output, just drop the column(s), like so.

df.groupby(by).apply(lambda a: a.drop(by, axis=1)[:])

Output:

         B
A         
one   0  0
      1  1
      5  5
three 3  3
      4  4
two   2  2

Here, I am not sure as to why .iloc[:] does not work instead of [:] at the end. So, if there are some issues in future due to updates (or at present), .iloc[:len(a)] also works.

Footnotes

1. python - How to print a groupby object - Stack Overflow ↩