A Pandas Dataframe is a 2-dimensional data structure that displays data in tables with rows and columns.

In this article, you'll learn how to rename columns in a Pandas Dataframe by using:

  • The rename() function.
  • A List.
  • The set_axis() function.

How to Rename a Column in Pandas Using the rename() Function

In this section, you'll see a practical example of renaming a Pandas Dataframe using the rename() function.

Let's begin by passing data into a Dataframe object: 

import pandas as pd

students = {
    "firstname": ["John", "Jane", "Jade"], 
    "lastname": ["Doe", "Done", "Do"]
}

# convert student names into a Dataframe
df = pd.DataFrame(students)

print(df)
# Output
  firstname lastname
0      John      Doe
1      Jane     Done
2      Jade       Do

In the example above, we created a Python dictionary which we used to store the firstname and lastname of students.

We then converted the dictionary to a Dataframe by passing it as a parameter to the Pandas Dataframe object: pd.DataFrame(students).

When printed to the console, we had this table printed out:

  firstname lastname
0      John      Doe
1      Jane     Done
2      Jade       Do

The goal here is to rename the columns. We can do that using the rename() function.

Here's what the syntax looks like:

df.rename(columns={"OLD_COLUMN_VALUE": "NEW_COLUMN_VALUE"})

Let's go ahead and change the column names (firstname and lastname) in the table from lowercase to uppercase (FIRSTNAME and LASTNAME). 

import pandas as pd

students = {
    "firstname": ["John", "Jane", "Jade"], 
    "lastname": ["Doe", "Done", "Do"]
}

# convert student names into a Dataframe
df = pd.DataFrame(students)

df.rename(columns={"firstname": "FIRSTNAME", "lastname": "LASTNAME"}, inplace=True)

print(df)
# Output
  FIRSTNAME LASTNAME
0      John      Doe
1      Jane     Done
2      Jade       Do

In the code above, we specified that the columns firstname and lastname should be renamed to FIRSTNAME and LASTNAME, respectively: df.rename(columns={"firstname": "FIRSTNAME", "lastname": "LASTNAME"}, inplace=True)

You'll notice that we added the inplace=True parameter. This helps in persisting the new changes in the Dataframe. Delete the parameter and see what happens ;)

You can rename the columns to whatever you want. For instance, we can use SURNAME instead of lastname by doing this:

import pandas as pd

students = {
    "firstname": ["John", "Jane", "Jade"], 
    "lastname": ["Doe", "Done", "Do"]
}

# convert student names into a Dataframe
df = pd.DataFrame(students)
df.rename(columns={"firstname": "FIRSTNAME", "lastname": "SURNAME"}, inplace=True)

print(df)
# Output
  FIRSTNAME SURNAME
0      John     Doe
1      Jane    Done
2      Jade      Do

You can change just one column name, too. You are not required to change all the column names at the same time.

How to Rename a Column in Pandas Using a List

You can access the column names of a Dataframe using df.columns. Consider the table below:

  firstname lastname
0      John      Doe
1      Jane     Done
2      Jade       Do

We can print out the column names with the code below:

print(df.columns)

# Index(['firstname', 'lastname'], dtype='object')

Using that, we can rename the column of a Dataframe. Here's an example:

import pandas as pd

students = {
    "firstname": ["John", "Jane", "Jade"], 
    "lastname": ["Doe", "Done", "Do"]
}

# convert student names into a Dataframe
df = pd.DataFrame(students)
df.columns = ["FIRSTNAME", "SURNAME"]

print(df)
# Output
  FIRSTNAME SURNAME
0      John     Doe
1      Jane    Done
2      Jade      Do

In the example above, we put the new column names in a List and assigned it to the Dataframe columns: df.columns = ["FIRSTNAME", "SURNAME"].

This will override the previous column names.

How to Rename a Column in Pandas Using the set_axis() Function

The syntax for renaming a column with the set_axis() function looks like this:

df.set_axis([NEW_COLUMN_NAME,...], axis="columns")

Here's a code example:

import pandas as pd

students = {
    "firstname": ["John", "Jane", "Jade"], 
    "lastname": ["Doe", "Done", "Do"]
}

# convert student names into a Dataframe
df = pd.DataFrame(students)

df.set_axis(["FIRSTNAME", "SURNAME"], axis="columns", inplace=True) 

print(df)
# Output
  FIRSTNAME SURNAME
0      John     Doe
1      Jane    Done
2      Jade      Do

Note that the inplace=True parameter might raise a warning because it's deprecated for the set_axis() function and will be replaced in the future.

Summary

In this article, we talked about renaming a column in Pandas.

We saw different methods that can be used to rename a Pandas Dataframe column with code examples.

Happy coding!