Rename columns in pandas

In this article, we will be renaming columns in a pandas dataframe. First, let's import pandas and create an example dataframe

# Import modules
import pandas as pd

# Example dataframe

raw_data  = {'fruit': ['Banana', 'Orange', 'Apple', 'lemon', "lime", "plum"], 
        'color': ['yellow', 'orange', 'red', 'yellow', "green", "purple"], 
        'kcal': [89, 47, 52, 15, 30, 28]
    }

df = pd.DataFrame(raw_data, columns = ['fruit', 'color', 'kcal'])
df

	fruit	color	kcal
0	Banana	yellow	89
1	Orange	orange	47
2	Apple	red	52
3	lemon	yellow	15
4	lime	green	30
5	plum	purple	28

The most flexible method for renaming columns in pandas is the rename method. It takes a dictornnary as an argument where : * the keys are the old names * the values are the new names you also need to specify the axis.

This method can be used to rename either one or multiple columns

df = df.rename({"fruit" : "produce", "kcal": "energy"}, axis="columns")
df

	produce	color	energy
0	Banana	yellow	89
1	Orange	orange	47
2	Apple	red	52
3	lemon	yellow	15
4	lime	green	30
5	plum	purple	28

If you want to rename all the columns at once, a common method is to rewrite the columns attribute of the dataframe

df.columns = ["nice fruit", "bright color", "light kcal"]
df

	nice fruit	bright color	light kcal
0	Banana	yellow	89
1	Orange	orange	47
2	Apple	red	52
3	lemon	yellow	15
4	lime	green	30
5	plum	purple	28

If the only thing you are doing is replacing a space with an underscore, an even better method is to use the str.replace method since you don't have to type all the column names

df.columns = df.columns.str.replace(" ", "_")
df

	nice_fruit	bright_color	light_kcal
0	Banana	yellow	89
1	Orange	orange	47
2	Apple	red	52
3	lemon	yellow	15
4	lime	green	30
5	plum	purple	28

Similarly, you can use other str methods such as : * capitalize : in order to converts first character to capital letter * lower : in order to have lowercase column names * upper : in order to have uppercase column names * etc.

df.columns = df.columns.str.capitalize()
df

	Nice_fruit	Bright_color	Light_kcal
0	Banana	yellow	89
1	Orange	orange	47
2	Apple	red	52
3	lemon	yellow	15
4	lime	green	30
5	plum	purple	28

Finaly, if you only need to add a prefix or a suffix to the columns, you can use the add_prefix method

df.add_prefix("pre_")

	pre_Nice_fruit	pre_Bright_color	pre_Light_kcal
0	Banana	yellow	89
1	Orange	orange	47
2	Apple	red	52
3	lemon	yellow	15
4	lime	green	30
5	plum	purple	28

or the add_suffix method

df.add_suffix("_post")

	Nice_fruit_post	Bright_color_post	Light_kcal_post
0	Banana	yellow	89
1	Orange	orange	47
2	Apple	red	52
3	lemon	yellow	15
4	lime	green	30
5	plum	purple	28