Multiply two columns in a pandas dataframe and add the result into a new column

Given a DataFrame, we need to multiply two columns in this DataFrame and add the result into a new column. By Pranit Sharma Last updated : September 25, 2023

Pandas is a special tool that allows us to perform complex manipulations of data effectively and efficiently. Inside pandas, we mostly deal with a dataset in the form of DataFrame. DataFrames are 2-dimensional data structures in pandas. DataFrames consist of rows, columns, and data.

Problem statement

Given a DataFrame, we need to multiply two columns in this DataFrame and add the result into a new column.

Multiplying two columns in a pandas dataframe and add the result into a new column

For this purpose, we will first create a DataFrame, the dataframe will contain 2 columns initially and we will perform a row-wise product of both columns and store all the values in a list. Finally, we will assign this list to a new column of the DataFrame.

Let us understand with the help of an example,

Python program to multiply two columns in a pandas dataframe and add the result into a new column

# Importing pandas package
import pandas as pd

# Creating a Dictionary
d = {
    'A':[10,20,30,40,50],
    'B': [10,20,30,40,50]
}

# Creating a DataFrame
df = pd.DataFrame(d)

# Display original DataFrame
print("Original DataFrame:\n",df,"\n")

# Creating a list of values
list = []
for i in range(len(df['A'])):
    a = (df['A'][i]*df['B'][i])
    list.append(a)

# Creating a new column and assigning 
# its values as the list defined above
df['Product'] = list

# Display modified DataFrame
print("Modified DataFrame:\n",df)