Replace Multiple Values in a Dataset using Pandas

In this tutorial, we’ll see how to change multiple values in a dataset using the pandas replace() method. Pandas is a python library for data manipulation and analysis which provides a wide range of features to make the dataset usable.

Replace Multiple Values in a Dataset

Follow the below step-by-step tutorial to replace multiple values in a dataset using the pandas library.

1. Import Pandas

Start by importing Pandas into your code.

import pandas as pd

2. Sample Data

We will use the following dataset as an example and implement it in a Pandas DataFrame where ‘columns’ represent the column heading of the Dataset, as defined in the DataFrame.

import pandas as pd
data = pd.DataFrame([
    ['Jack',25,'USA'],
    ['Rohan',20,'India'],
    ['Sam',23,'France'],
    ['Rini',19,'UK'],
    ['Tywin',16,'Ireland']],

columns=['Name','Age', 'Country'])

When the program is executed, and the DataFrame is printed using the print method, the above code results in the following output – having 3 columns ‘Name’, ‘Age’, ‘Country’.

print (data)

Sample Data To Replace Multiple Values in Python DataFrame — Sample Data To Replace Multiple Values

3. Replacing Values using replace() Method

Using the replace() method in pandas replaces a specified value with another specified value. In our sample dataset created we wish to change the USA to India in the ‘Country’ column:

new_data = data.replace({'Country':{'USA':'India'}})

print (new_data)

Replacing Single Value In Pandas Dataframe — Replacing Single Value In Dataframe

Now, if we try to replace multiple values at once in a DataFrame, as like 25 to 23, also 16 to 18 in the Age column and ‘Tywin’ to ‘Stark’ in the Name column, here’s what the code would look like:

updated_data = new_data.replace({'Age': {25:23, 16:18}, 'Name':{'Tywin':'Stark'}})

print(updated_data)

Final output after changing the desired values:

Replacing Multiple Value In Pandas Dataframe — Replacing Multiple Value In Dataframe

Complete Code to Replace Multiple Values in a Dataframe

Try the code below to see how the replace() method in Python works.

import pandas as pd
data = pd.DataFrame([
    ['Jack',25,'USA'],
    ['Rohan',20,'India'],
    ['Sam',23,'France'],
    ['Rini',19,'UK'],
    ['Tywin',16,'Ireland']],

columns=['Name','Age', 'Country'])
print (data)

print('\n')

new_data = data.replace({'Country':{'USA':'India'}})

print (new_data)

updated_data = new_data.replace({'Age': {25:23, 16:18}, 'Name':{'Tywin':'Stark'}})

print('\n')
print(updated_data)

Conclusion

That’s It! for this tutorial. Hope you have learned well how to replace multiple values in a Pandas DataFrame in Python. Stay tuned to AskPython for more such tutorials.