Python | Pandas Series.bfill()

Pandas series is a One-dimensional ndarray with axis labels. The labels need not be unique but must be a hashable type. The object supports both integer- and label-based indexing and provides a host of methods for performing operations involving the index.

Pandas Series.bfill() function is synonym for the backward fill method. This function is used to fill the missing values in the given series object.

Syntax: Series.bfill(axis=None, inplace=False, limit=None, downcast=None)

Parameter :
axis : axis = 1
inplace : make changes to the same object
limit : maximum number of consecutive missing values to fill

Returns : Series

Example #1: Use Series.bfill() function to fill the missing values in the given series object.

# importing pandas as pd
import pandas as pd

# Creating the Series
sr = pd.Series(['New York', 'Chicago', 'Toronto', None, 'Rio'])

# Create the Index
index_ = ['City 1', 'City 2', 'City 3', 'City 4', 'City 5']

# set the index
sr.index = index_

# Print the series
print(sr)

Output :

Now we will use Series.bfill() function to fill the missing values in the given series object.

# fill the missing values using backward fill method
result = sr.bfill()

# Print the result
print(result)

Output :

As we can see in the output, the Series.bfill() function has successfully filled the missing values in the given series object using the backward fill method.

Example #2 : Use Series.bfill() function to fill the missing values in the given series object.

# importing pandas as pd
import pandas as pd

# Creating the Series
sr = pd.Series([100, None, None, 18, 65, None, 32, 10, 5, 24, None])

# Create the Index
index_ = pd.date_range('2010-10-09', periods = 11, freq ='M')

# set the index
sr.index = index_

# Print the series
print(sr)

Output :

Now we will use Series.bfill() function to fill the missing values in the given series object.

# fill the missing values using backward fill method
result = sr.bfill()

# Print the result
print(result)

Output :

As we can see in the output, the Series.bfill() function has successfully filled the missing values in the given series object using the backward fill method. Notice the last value has not been filled because there is no valid value in the series after that element.