将项目添加到pandas.Series？

Question

我想为我添加一个整数pandas.Series
这是我的代码:

import pandas as pd
input = pd.Series([1,2,3,4,5])
input.append(6)

当我运行它时,我收到以下错误:

Traceback (most recent call last):
  File "<pyshell#9>", line 1, in <module>
    f.append(6)
  File "C:\Python33\lib\site-packages\pandas\core\series.py", line 2047, in append
    verify_integrity=verify_integrity)
  File "C:\Python33\lib\site-packages\pandas\tools\merge.py", line 878, in concat
    verify_integrity=verify_integrity)
  File "C:\Python33\lib\site-packages\pandas\tools\merge.py", line 954, in __init__
    self.new_axes = self._get_new_axes()
  File "C:\Python33\lib\site-packages\pandas\tools\merge.py", line 1146, in _get_new_axes
    concat_axis = self._get_concat_axis()
  File "C:\Python33\lib\site-packages\pandas\tools\merge.py", line 1163, in _get_concat_axis
    indexes = [x.index for x in self.objs]
  File "C:\Python33\lib\site-packages\pandas\tools\merge.py", line 1163, in <listcomp>
    indexes = [x.index for x in self.objs]
AttributeError: 'int' object has no attribute 'index'

我该如何解决这个问题？

Answer 1

将附加项转换为Series:

>>> ds = pd.Series([1,2,3,4,5]) 
>>> ds.append(pd.Series([6]))
0    1
1    2
2    3
3    4
4    5
0    6
dtype: int64

或使用DataFrame:

>>> df = pd.DataFrame(ds)
>>> df.append([6], ignore_index=True)
   0
0  1
1  2
2  3
3  4
4  5
5  6

如果你的索引没有间隙,那么最后一个选项,

>>> ds.set_value(max(ds.index) + 1,  6)
0    1
1    2
2    3
3    4
4    5
5    6
dtype: int64

你可以使用numpy作为最后的手段:

>>> import numpy as np
>>> pd.Series(np.concatenate((ds.values, [6])))

Answer 2

使用set_value会生成警告：

FutureWarning：set_value 已弃用，并将在未来版本中删除。请改用 .at[] 或 .iat[] 访问器

所以你可以at这样使用：

input.at[input.index[-1]+1]=6