Pandas Series: append() function

Last update on September 15 2022 12:55:21 (UTC/GMT +8 hours)

Concatenate two or more Pandas series

The append() function is used to concatenate two or more Series.

Syntax:

Series.append(self, to_append, ignore_index=False, verify_integrity=False)

Name	Description	Type/Default Value	Required / Optional
to_append	Series to append with self.	Series or list/tuple of Series	Required
ignore_index	If True, do not use the index labels.	bool Default Value: False	Required
verify_integrity	If True, raise Exception on creating index with duplicates.	bool Default Value: False	Required

Returns: Series - Concatenated Series.

Notes:

Iteratively appending to a Series can be more computationally intensive than a single concatenate. A better solution is to append values to a list and then concatenate the list with the original Series all at once.

Example:

Python-Pandas Code:

import numpy as np
import pandas as pd
s1 = pd.Series([2, 3, 4])
s2 = pd.Series([5, 6, 7])
s3 = pd.Series([5, 6, 7], index=[4, 5, 6])
s1.append(s2)

Output:

0    2
1    3
2    4
0    5
1    6
2    7
dtype: int64

Python-Pandas Code:

import numpy as np
import pandas as pd
s1 = pd.Series([2, 3, 4])
s2 = pd.Series([5, 6, 7])
s3 = pd.Series([5, 6, 7], index=[4, 5, 6])
s1.append(s3)

Output:

0    2
1    3
2    4
4    5
5    6
6    7
dtype: int64

Example - With ignore_index set to True:

Python-Pandas Code:

import numpy as np
import pandas as pd
s1 = pd.Series([2, 3, 4])
s2 = pd.Series([5, 6, 7])
s3 = pd.Series([5, 6, 7], index=[4, 5, 6])
s1.append(s2, ignore_index=True)

Output:

0    2
1    3
2    4
3    5
4    6
5    7
dtype: int64

With verify_integrity set to True:

s1.append(s2, verify_integrity=True) Traceback (most recent call last): ... ValueError: Indexes have overlapping values: [0, 1, 2]

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