Apply uppercase to a column in Pandas dataframe in Python

In this tutorial, we are going to see how to make a column of names to uppercase in DataFrame. Let's see different ways to achieve our goal.

Using str.upper() Method

We can convert a column to uppercase using the str.upper() method. This is the most common and efficient approach for string operations in pandas.

# importing the pandas package
import pandas as pd

# data for DataFrame
data = {
    'Name': ['Hafeez', 'Aslan', 'Kareem'],
    'Age': [19, 21, 18],
    'Profession': ['Developer', 'Engineer', 'Artist']
}

# creating DataFrame
data_frame = pd.DataFrame(data)

# displaying the DataFrame
print('---------------------Before-------------------')
print(data_frame)
print()

# making the Name column strings to upper case
data_frame['Name'] = data_frame['Name'].str.upper()

# displaying the DataFrame
print('---------------------After-------------------')
print(data_frame)

---------------------Before-------------------
     Name  Age Profession
0  Hafeez   19  Developer
1   Aslan   21   Engineer
2  Kareem   18     Artist

---------------------After-------------------
     Name  Age Profession
0  HAFEEZ   19  Developer
1   ASLAN   21   Engineer
2  KAREEM   18     Artist

Using apply() Method

We can also achieve the same result using the apply() method with a lambda function. This approach is more flexible for custom transformations.

# importing the pandas package
import pandas as pd

# data for DataFrame
data = {
    'Name': ['Hafeez', 'Aslan', 'Kareem'],
    'Age': [19, 21, 18],
    'Profession': ['Developer', 'Engineer', 'Artist']
}

# creating DataFrame
data_frame = pd.DataFrame(data)

# displaying the DataFrame
print('---------------------Before-------------------')
print(data_frame)
print()

# making the Name column strings to upper case
data_frame['Name'] = data_frame['Name'].apply(lambda name: name.upper())

# displaying the DataFrame
print('---------------------After-------------------')
print(data_frame)

---------------------Before-------------------
     Name  Age Profession
0  Hafeez   19  Developer
1   Aslan   21   Engineer
2  Kareem   18     Artist

---------------------After-------------------
     Name  Age Profession
0  HAFEEZ   19  Developer
1   ASLAN   21   Engineer
2  KAREEM   18     Artist

Comparison

Conclusion

Use str.upper() for simple uppercase conversion as it's more efficient. The apply() method is better suited for complex transformations that require custom logic.