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?

possible duplicate of [How to add a single item to a Pandas Series](http://stackoverflow.com/questions/13331518/how-to-add-a-single-item-to-a-pandas-series) — Amelio Vazquez-Reina, Dec 03 '14 at 16:14
None of these questions are mine. Also, your question was asked 12 months ago, but the one I linked to was asked over two years ago. — Amelio Vazquez-Reina, Dec 03 '14 at 22:11

alko · Accepted Answer · 2013-12-07T13:54:02.077

38

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])))

edited Dec 07 '13 at 13:54

answered Dec 07 '13 at 13:45

alko

46,136
12
94
102

3

as of today, .set_value() is deprecated, use .at()/.iat() instead – comte Apr 11 '18 at 07:39
As Comte says, set_value deprecated. See Gormoruk's answer for the correct solution. (https://pandas.pydata.org/pandas-docs/version/0.23.4/generated/pandas.Series.at.html#pandas.Series.at) – markling Jan 30 '20 at 14:26
Note that `append` is now [deprecated](https://pandas.pydata.org/pandas-docs/version/1.5/whatsnew/v1.4.0.html#whatsnew-140-deprecations-frame-series-append) and has been removed in pandas 2.0.0, [`concat`](https://pandas.pydata.org/docs/reference/api/pandas.concat.html) could be used as replacement. – mozway Apr 26 '23 at 09:49
As `append` is deprecated from pandas 2.0.0, we can use `_append`. e.g. - `ds._append(pd.Series([6]))` – Pinaki May 30 '23 at 10:05

score 5 · Answer 2 · edited Sep 13 '20 at 20:56

5

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

edited Sep 13 '20 at 20:56

bouteillebleu

2,456
23
32

answered Jul 28 '18 at 08:43

Attila.H

61
1
6

Mak2006 · Answer 3 · 2020-05-31T22:48:52.673

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

Add item to pandas.Series?

3 Answers3

Linked

Related