Python Language Writing to CSV from String or List


Writing to a .csv file is not unlike writing to a regular file in most regards, and is fairly straightforward. I will, to the best of my ability, cover the easiest, and most efficient approach to the problem.


open ("/path/", "mode")Specify the path to your CSV file
open (path, "mode")Specify mode to open file in (read, write, etc.)
csv.writer(file, delimiter)Pass opened CSV file here
csv.writer(file, delimiter=' ')Specify delimiter character or pattern


open( path, "wb")

"wb" - Write mode.

The b parameter in "wb" we have used, is necessary only if you want to open it in binary mode, which is needed only in some operating systems like Windows.

csv.writer ( csv_file, delimiter=',' )

Here the delimiter we have used, is ,, because we want each cell of data in a row, to contain the first name, last name, and age respectively. Since our list is split along the , too, it proves rather convenient for us.

Basic Write Example

import csv

#------ We will write to CSV in this function ------------

def csv_writer(data, path):
    #Open CSV file whose path we passed.
    with open(path, "wb") as csv_file:
        writer = csv.writer(csv_file, delimiter=',')
        for line in data:

#---- Define our list here, and call function ------------

if __name__ == "__main__":

    data = our list that we want to write. 
    Split it so we get a list of lists.
    data = ["first_name,last_name,age".split(","),

    # Path to CSV file we want to write to.
    path = "output.csv"
    csv_writer(data, path)

Appending a String as a newline in a CSV file

def append_to_csv(input_string):
    with open("fileName.csv", "a") as csv_file:
        csv_file.write(input_row + "\n")