How to append elements to a Pandas series?

In Pandas, you can append elements to a Series using the append() method or the newer concat() function. The append() method allows you to combine two Series, but note that it's deprecated in newer Pandas versions in favor of concat().

Using append() Method

The traditional approach uses the append() method to combine Series ?

import pandas as pd

s1 = pd.Series([10, 20, 30, 40, 50])
s2 = pd.Series([11, 22, 33, 44, 55])

print("S1:")
print(s1)
print("\nS2:")
print(s2)

appended_series = s1.append(s2)
print("\nFinal Series after appending:")
print(appended_series)

S1:
0    10
1    20
2    30
3    40
4    50
dtype: int64

S2:
0    11
1    22
2    33
3    44
4    55
dtype: int64

Final Series after appending:
0    10
1    20
2    30
3    40
4    50
0    11
1    22
2    33
3    44
4    55
dtype: int64

Using concat() Method (Recommended)

The modern approach uses pd.concat() which is more flexible and efficient ?

import pandas as pd

s1 = pd.Series([10, 20, 30, 40, 50])
s2 = pd.Series([11, 22, 33, 44, 55])

# Using concat instead of append
appended_series = pd.concat([s1, s2])
print("Using concat():")
print(appended_series)

# Reset index to get continuous numbering
appended_reset = pd.concat([s1, s2], ignore_index=True)
print("\nWith reset index:")
print(appended_reset)

Using concat():
0    10
1    20
2    30
3    40
4    50
0    11
1    22
2    33
3    44
4    55
dtype: int64

With reset index:
0    10
1    20
2    30
3    40
4    50
5    11
6    22
7    33
8    44
9    55
dtype: int64

Appending Individual Elements

You can also append individual elements by creating a new Series ?

import pandas as pd

original_series = pd.Series([1, 2, 3, 4])
new_element = pd.Series([5])

# Append single element
result = pd.concat([original_series, new_element], ignore_index=True)
print("Original series with new element:")
print(result)

Original series with new element:
0    1
1    2
2    3
3    4
4    5
dtype: int64

Key Points

• The append() method is deprecated in Pandas 1.4.0+
• Use pd.concat() for combining Series
• Use ignore_index=True to reset the index numbering
• Both methods return a new Series without modifying the original

Conclusion

Use pd.concat() instead of append() for combining Pandas Series. The concat() method is more efficient and is the recommended approach in modern Pandas versions.