Replacing column value of a CSV file in Python

Let us see how we can replace the column value of a CSV file in Python. CSV file is nothing but a comma-delimited file.

Method 1: Using Native Python way

Using replace() method, we can replace easily a text into another text. In the below code, let us have an input CSV file as “csvfile.csv” and be opened in “read” mode. The join() method takes all lines of a CSV file in an iterable and joins them into one string. Then, we can use replace() method on the entire string and can perform single/multiple replacements. In the entire string, the given text is searched and replaced with the specified text.

Example:

The input file will be:

Output:

Code :

# reading the CSV file
text = open(“csvfile.csv”, “r”)

#join() method combines all contents of
# csvfile.csv and formed as a string
text = ‘’.join([i for i in text])

# search and replace the contents
text = text.replace(“EmployeeName”, “EmpName”)
text = text.replace(“EmployeeNumber”, “EmpNumber”)
text = text.replace(“EmployeeDepartment”, “EmpDepartment”)
text = text.replace(“lined”, “linked”)

# output.csv is the output file opened in write mode
x = open(“output.csv”,”w”)

# all the replaced text is written in the output.csv file
x.writelines(text)
x.close()

Method 2: Using Pandas DataFrame

We can read the CSV file as a DataFrame and then apply the replace() method.

Output:

Code :

# importing the module
import pandas as pd

# making data frame from the csv file
dataframe = pd.read_csv(“csvfile1.csv”)

# using the replace() method
dataframe.replace(to_replace =”Fashion”,
value = “Fashion industry”,
inplace = True)
dataframe.replace(to_replace =”Food”,
value = “Food Industry”,
inplace = True)
dataframe.replace(to_replace =”IT”,
value = “IT Industry”,
inplace = True)

# writing the dataframe to another csv file
dataframe.to_csv(‘outputfile.csv’,
index = False)