What happens if the specified index is not present in the series Python Pandas?

When the index values are customized, they are accessed using series_name[‘index_value’]. The ‘index_value’ passed to series is tried to be matched to the original series. If it is found, that corresponding data is also displayed on the console.

When the index that is tried to be accessed is not present in the series, it throws an error. It has been shown below.


 Live Demo

import pandas as pd
my_data = [34, 56, 78, 90, 123, 45]
my_index = ['ab', 'mn' ,'gh','kl', 'wq', 'az']
my_series = pd.Series(my_data, index = my_index)
print("The series contains following elements")
print("Accessing elements using customized index")


The series contains following elements
ab  34
mn  56
gh  78
kl  90
wq  123
az  45
dtype: int64
Accessing elements using customized index
Traceback (most recent call last):
KeyError: 'mm'


  • The required libraries are imported, and given alias names for ease of use.

  • A list of data values is created, that is later passed as a parameter to the ‘Series’ function present in the ‘pandas’ library

  • Next, customized index values (that are passed as parameter later) are stored in a list.

  • The series is created and index list and data are passed as parameters to it.

  • The series is printed on the console.

  • Since the index values are customized, they are used to access the values in the series like series_name[‘index_name’].

  • It is searched for in the series but when it is not found, it throws a ‘KeyError’.

  • It is then printed on the console.