View Discussion Show Improve Article Save Article View Discussion Improve Article Save Article 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:  Python3
Output: Method 2: Using Pandas DataFrame We can read the CSV file as a DataFrame and then apply the replace() method. Python3
Output: Below is a quick tutorial on using a type of “find and replace” across a CSV file or you could do this find and replace on a TXT file too. I’m not a developer, just another blogger, blogging about learning python. I’m building use cases that are similar to a typical business analyst or data analyst. You get a CSV file or TEXT file and want to scrape over the entire file, and output it with your modifications. Find and replace is the term I would think you would google if you wanted to do a find and replace in python over a CSV. Here’s a typical CSV file. Delimited by a comma. Name,Number,Rank,Website,Flag,Cat→ Save file as input.csv Python, without any downloaded libraries, will do a find and replace on the data above. You can copy and paste the data above into a .txt file, and change the extension to .csv — if you don’t have an excel software on your computer, or you can use Google sheets and make your own data problem. Our goal is to clean the 3. The 3 in the https://tylergarr3tt.com link because it’s not accurate. For whatever reason this is going to be used by a developer and they are asking me to find and replace the “errors.” Errors in the sample data generate a use case to learn how to do a find and replace on a CSV file, which taught me that using the a previous “text file” tutorial, I was able to handle the same ETL like solution, with simple python code, and no odd libraries to be imported. Our use case will generate a full “find and replace python solution” and a few more obvious data issues. We will remove “3” and replace it with “e” in python below, to help us move down a path of learning and solving your use case today. The code to find and replace anything on a CSV using pythontext = open("input.csv", "r")We are not using any “imports” because this is all native python capability. Let’s see what the output looks like. Name,Number,Rank,Website,Flag,CatSuccessfully cleaning the “3” and also adding an “e” where our “3” used to be. Look at line 2 & line 3 before: Jeff,36,2,https://tylergarrett.com,No,0Look at line 2 & line 3 after: Jeff,e6,2,https://tylergarrett.com,No,0The small portion of code: text = ''.join([i for i in text]) \Allows you to “find and replace” using one line of code. It looks like 2 lines of code because python lets you put a space and a “\” in front of a long line of code. The space + “\” lets me see what I’m doing easier that writing one wrapping line of code. An example that may require a “ \” in front of your code, looks something like…because it’s easier to read. Above image of code is an exaggeration to show you that python lets you break up your find and replace or you can do it in one line. I do it because I would go absolutely crazy if it wasn’t for that little feature, so if you’re like me, woop woop. This is a big help, otherwise
text = ''.join([i for i in text]).replace("3", "e")Above code lets us quickly replace “3”’s with “e”’s and lets us heal our link column in the csv file. Find and replace may require a more granular approach which will be covered in another lesson. Final code to find and replace text in a CSV with pythonFind and replace text or letters in a csv with python is simple, super fast, faster than any SQL stuff I’ve played with in the past, so — if you need to bulk process a CSV or TEXT file — python is a great direction because it’s easy to understand. text = open("input.csv", "r")‘’.join is cool because it allows you to add anything, to each row of data. Notice how… text = '1'.join([i for i in text]) \Adds a “1” to each row of data… Name,Number,Rank,Website,Flag,CatHow exciting… text = open("input.csv", "r")Generates… Name,Number,Rank,Website,Flag,CatFind and replace in python, using the basics. You can use a .txt file too, for both input and output. Later you will learn split() is a lot of fun to use. By Tyler Garrett Built a Tableau Consulting thing and now i do other stuff. How do I replace data in a CSV file in Python?Approach. Import module.. Open csv file and read its data.. Find column to be updated.. Update value in the csv file using replace() function.. How do I find and replace in a CSV file?When working with a CSV file it is often necessary to find data contained within and sometimes replace it. Find & Replace is used for just this. You can access it from the Edit > Find & Replace menu or by pressing Ctrl-F on the keyboard.
How do I edit a CSV file in Python?Editing the contents of an existing CSV file will require the following steps: read in the CSV file data, edit the lists (Update information, append new information, delete information), and then write the new data back to the CSV file.
How do I replace a string in a python file?To replace text in a file we are going to open the file in read-only using the open() function. Then we will t=read and replace the content in the text file using the read() and replace() functions.
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