Question

例如，我有一个非常简单的数据框：

values = pd.Series(i for i in range(5))
rows = pd.Series(['a', 'b', 'a', 'a', 'b'])
columns = pd.date_range('20130101',periods=5)

df = pd.DataFrame({'values': values, 'rows': rows, 'columns': columns})

以及它的外观：

              columns rows  values
0 2013-01-01 00:00:00    a       0
1 2013-01-02 00:00:00    b       1
2 2013-01-03 00:00:00    a       2
3 2013-01-04 00:00:00    a       3
4 2013-01-05 00:00:00    b       4

当我尝试制作没有边距（总计）的枢轴时，我取得了成功：

pivot = pd.pivot_table(
    data=df,
    rows='rows',
    cols='columns',
    values='values',
    margins=False
)

看起来如何：

columns  2013-01-01  2013-01-02  2013-01-03  2013-01-04  2013-01-05
rows                                                               
a                 0         NaN           2           3         NaN
b               NaN           1         NaN         NaN           4

但如果我想创建带边距的轴：

pivot = pd.pivot_table(
    data=df,
    rows='rows',
    cols='columns',
    values='values',
    margins=True
)

我收到错误：

Traceback (most recent call last):
  File "./test.py", line 17, in <module>
    margins=True
  File "/usr/local/lib/python2.6/dist-packages/pandas/tools/pivot.py", line 135, in pivot_table
    cols=cols, aggfunc=aggfunc)
  File "/usr/local/lib/python2.6/dist-packages/pandas/tools/pivot.py", line 174, in _add_margins
    piece[all_key] = margin[key]
  File "/usr/local/lib/python2.6/dist-packages/pandas/core/frame.py", line 2119, in __setitem__
    self._set_item(key, value)
  File "/usr/local/lib/python2.6/dist-packages/pandas/core/frame.py", line 2166, in _set_item
    NDFrame._set_item(self, key, value)
  File "/usr/local/lib/python2.6/dist-packages/pandas/core/generic.py", line 679, in _set_item
    self._data.set(key, value)
  File "/usr/local/lib/python2.6/dist-packages/pandas/core/internals.py", line 1781, in set
    self.insert(len(self.items), item, value)
  File "/usr/local/lib/python2.6/dist-packages/pandas/core/internals.py", line 1801, in insert
    new_items = self.items.delete(loc)
  File "/usr/local/lib/python2.6/dist-packages/pandas/core/index.py", line 2610, in delete
    new_labels = [np.delete(lab, loc) for lab in self.labels]
  File "/usr/lib/pymodules/python2.6/numpy/lib/function_base.py", line 3339, in delete
    "invalid entry")
ValueError: invalid entry

Python版本：2.6.8
熊猫版：0.12.0
系统：Debian Linux，内核为3.2.0，64位。

感谢。

Answer 1

我可以重现您的问题。这听起来像个bug。至少我发现重新分配列名解决了这个问题：

df.columns = ['rows', 'columns', 'values']

pd.pivot_table(
    ...:     data=df,
    ...:     rows='rows',
    ...:     cols='columns',
    ...:     values='values',
    ...:     margins=True)
Out[34]: 
columns                     a    b  All
rows                                   
2013-01-01 00:00:00  0.000000  NaN    0
2013-01-02 00:00:00       NaN  1.0    1
2013-01-03 00:00:00  2.000000  NaN    2
2013-01-04 00:00:00  3.000000  NaN    3
2013-01-05 00:00:00       NaN  4.0    4
All                  1.666667  2.5    2

如何在Pandas中创建具有总计（边距）的数据透视图？

1 个答案: