Data Structure
Networking
RDBMS
Operating System
Java
MS Excel
iOS
HTML
CSS
Android
Python
C Programming
C++
C#
MongoDB
MySQL
Javascript
PHP
Physics
Chemistry
Biology
Mathematics
English
Economics
Psychology
Social Studies
Fashion Studies
Legal Studies
- Selected Reading
- UPSC IAS Exams Notes
- Developer's Best Practices
- Questions and Answers
- Effective Resume Writing
- HR Interview Questions
- Computer Glossary
- Who is Who
How to retrieve the last valid index from a series object using pandas series.last_valid_index() method?
The pandas series.last_valid_index() method is used to get the index of the last valid element from the given series object. This means the last_valid_index() method returns the index of the last non_null element of the series.
It will return a single scalar based on the type of series index, and it will return None if the given series has all null/NA values or if it is empty. The method doesn’t have any parameters.
Example 1
Let’s create a pandas series object and retrieve the last valid index by using the last_valid_index() method.
# importing packages
import pandas as pd
import numpy as np
# create a series
s = pd.Series([None, 34, np.nan, 87], index=list('pqrs'))
print(s)
# apply last_valid_index() method
result = s.last_valid_index()
print("Result:")
print(result)Output
The output is as follows −
p NaN q 34.0 r NaN s 87.0 dtype: float64 Result: s
For the above example, the last valid index is “s”, because the element at index position s is not a Null/NA value.
Example 2
Here, let’s take an empty series object and see how the last_valid_index() method works for an empty series.
# importing packages
import pandas as pd
# create an empty series
sr = pd.Series([])
print(sr)
# apply last_valid_index() method
result = sr.last_valid_index()
print("Result:")
print(result)Output
The output is mentioned below −
Series([], dtype: float64) Result: None
The last_valid_index() method returned None for the empty series object.
Example 3
In this following example, we have created a pandas series object with all Null/Nan values and applied the last_valid_index() method to get the last valid index.
# importing packages
import pandas as pd
import numpy as np
# create a series
sr = pd.Series([None, np.nan])
print(sr)
# apply last_valid_index() method
result = sr.last_valid_index()
print("Result:")
print(result)Output
The output is given below −
0 NaN 1 NaN dtype: float64 Result: None
For this example, the last_valid_index() method returned None, because there is no valid element available in the given series object.
485 Views
