Add item to pandas.Series?

Question

I want to add an integer to my pandas.Series
Here is my code:

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

When i run this, i get the following error:

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'

How can I fix that?

Answer 1

Convert appended item to 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

or use DataFrame:

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

and last option if your index is without gaps,

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

And you can use numpy as a last resort:

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

Answer 2

Using set_value generates the warning:

FutureWarning: set_value is deprecated and will be removed in a future release. Please use .at[] or .iat[] accessors instead

So you can instead use at like this:

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

Answer 3

here is a one-line answer It is dependent on how the array is defined. If we use Series is a one d array. Use the array notation like x[index] = new value

example

import pandas as pd
input = pd.Series([1,2,3,4,5])
newval = 7 # say
input[len(input)] = newval

or use append if the array is being directly defined.

#if input is defined as []
input2 = [1, 2]
#input2[len(input2)] = 3 # does not work
input2.append(3) #works
input2