CODEWITHSUNDEEP
pythonpandasseries
oakca
oakca

Reputation: 1568

Pandas series add index and value at the beginning of the series object

I got a pandas Series object with an index starting from '2020-01-01 01:00:00+00:00' till 2020-12-19. I would like to add the index '2020-01-01 00:00:00+00:00' with the value np.nan.

data_dict[i]
date_time
2020-01-01 01:00:00+00:00    13
2020-01-01 02:00:00+00:00    13
2020-01-01 03:00:00+00:00    13
2020-01-01 04:00:00+00:00    13
2020-01-01 05:00:00+00:00    13
                              ...
2020-12-18 20:00:00+00:00    25
2020-12-18 21:00:00+00:00    25
2020-12-18 22:00:00+00:00    25
2020-12-18 23:00:00+00:00    25
2020-12-19 00:00:00+00:00    20

When I use:

nan = pd.Series([np.nan], index=['2020-01-01 00:00:00+00:00'])
data_dict[i].append(nan)
data_dict[i].sort_index()

seems like nothing happens?

data_dict[i]
date_time
2020-01-01 01:00:00+00:00    13
2020-01-01 02:00:00+00:00    13
2020-01-01 03:00:00+00:00    13
2020-01-01 04:00:00+00:00    13
2020-01-01 05:00:00+00:00    13
                              ...
2020-12-18 21:00:00+00:00    25
2020-12-18 22:00:00+00:00    25
2020-12-18 23:00:00+00:00    25
2020-12-19 00:00:00+00:00    20

How would I add it at the right place(ie: at the beginning of the series object)

Upvotes: 1

Views: 1273

Answers (1)

jezrael
jezrael

Reputation: 862661

If use .append new data are added to end of Series, for correct order sorting values of DatetimeIndex:

s = s1.append(s2).sort_index()

If need to append to start of Series, swap order - add second Series to first one:

s = s2.append(s1)

EDIT: Here is necessary assign back Series.append and create DatetimeIndex in added Series:

nan = pd.Series([np.nan], index=pd.to_datetime(['2020-01-01 00:00:00+00:00']))
data_dict[i] = data_dict[i].append(nan)
data_dict[i] = data_dict[i].sort_index()

Upvotes: 3

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