How to Writing into CSV File with Python Programming

how to write into a CSV file with a Python Programming?

So, Here I have given Python Code and CSV file which I was used in Tutorial.

Python Code:

import csv
with open("data.txt", "r") as dataFile:
   dataFileReader = csv.reader(dataFile)
   dataList = []
   for row in dataFileReader:
     if len (row) != 0:
       dataList = dataList + [row]
dataFile.close()
print(dataList)

name = input("Enter name: ")

secondName = input("Enter secondName: ")
value1 = input("value1: ")
value2 = input("value2: ")
value3 = input("value3: ")
with open("data.txt", "a") as dataFile:
  dataFileWriter = csv.writer(dataFile)
  dataFileWriter.writerow([name, secondName, value1, value2, value3])
dataFile.close()

CSV File :

ABC, XYZ, 1, 2, 3
PQR, WXY, 4, 5, 6
DEF, JKL, 7, 8, 9

This Python code is made for a view, imports, and write the comma separated files in python app. Also with this code user can read that file in the app also They can write in that file.

import csv
with open("data.txt", "r") as dataFile:
 dataFileReader = csv.reader(dataFile)
 dataList = []
 for row in dataFileReader:
 if len (row) != 0:
 dataList = dataList + [row]
dataFile.close()
print(dataList)

Above code is used for a view and import the CSV file. and for more detail of the code check 'Reading of CSV file in python programming'.

name = input("Enter name: ")

secondName = input("Enter secondName: ")
value1 = input("value1: ")
value2 = input("value2: ")
value3 = input("value3: ")

Now, form here writing part begins. Here above we can see for writing into CSV we have to take first input from users with an 'input' function. so I took five inputs for respectively name, secondName, value1, value2, value3.

Those variable's values depend on CSV file's data. Here in above CSV file, we have five variable where two of them have a string value and three of them have a numerical value.

with open("data.txt", "w") as dataFile:

 dataFileWriter = csv.writer(dataFile)
 dataFileWriter.writerow([name, secondName, value1, value2, value3])

Now, we have to reopen the CSV file because we did close once after that reading done. with 'with open' we can open that file and here all things are change is just defining symbol of the process. which has I put 'w' because we have to write into a file so for that this symbol is using. And the second line also has only one difference that we have to use 'csv.writer' instead of 'csv.reader'.

 As you seen name difference so might you get the mean of that name, but still the 'csv.writer' is used to make write operation on CSV file. Which is stored in a 'dataFile' variable. Now the last one line is used for an import the data by passing the array of variables in a same manner of the file. And this array will be written because of 'writerow' function which makes write into file row by row.  
And one important thing is, When we use 'w' symbol then it'll be altering the file data with the importing data. that means after this operation file's data will erase and imported data take place in the file. But if we use 'a' instead of 'w' so it'll add the new data after the old one.

with open("data.txt", "a") as dataFile:

Above one is the syntax for how you can 'a' symbol for an adding data into CSV file.

You can find this video tutorial of this as well by following:

Write into CSV file in Python Programming 

If you have any questions and queries, comment us below.