CSV FILE

CSV (Comma Separated Values) is a simple file format used to store data in tabular form such as excel sheet or database. 

Each line of the file is a data record. 

Each record consists of one or more fields, separated by commas. The csv module  is used  for working with CSV files in python. 

It is used to read and write tabular data in CSV format.

There are 3 main modes in which the files can be opened: Read, Write and Append mode.

Read mode (denoted by ‘r’): It reads contents from a file. The file should exist else it gives an error.

Write mode (denoted by ‘w’): It writes to a CSV file. If the file exists, it clears it and starts writing to it from the first row. Else, if the file does not exist, it is created and then the data is written to it.

Append mode (denoted by ‘a’): It writes rows to a pre-existing file. It is different from write mode as it does not clear the existing rows of the CSV file, it just adds the rows below them.

 Open notepad and type contents as

name,class, marks

ajay,12,75

vijay,11,85

then save the file named as"abc.csv"

# reading csv file contents

import csv 

f=open("abc.csv",'r')

r=csv.reader(f)  # canvert file object into reader object

for row in r:

        print(row)

Every record is stored in reader object in form of List 

  write, append, serach, delete and display operations in CSV File 

import csv

def Add():

    f=open("abc.csv","w")

    r=csv.writer(f)

    name=input("Enter name")

    rollno=int(input("Enter rollno "))

    marks=int(input("Enter marks"))

    cls=int(input("Enter class"))

    l=[name,rollno,marks,cls]

    r.writerow(l)

    f.close()

def Append():

    f=open("abc.csv","a")

    r=csv.writer(f)

    name=input("Enter name")

    rollno=int(input("Enter rollno "))

    marks=int(input("Enter marks"))

    cls=int(input("Enter class"))

    l=[name,rollno,marks,cls]

    r.writerow(l)

    f.close()

#Search record rollno wise

def search():

    f=open("abc.csv","r",newline="\n")

    r=csv.reader(f)

    for i in r:

        if(int(i[1]))==2:

            print(i)

    f.close()

    #delete record for given rollno

def delete():

    rollno=int(input("enter rollno for deletion"))

    f=open("abc.csv","r",newline="\n")

    r=csv.reader(f)

    l=[]

    for i in r:

        if(int(i[1]))!=rollno:

            l.append(i)

            #print(i,"Record deleted")

    f.close()

    f=open("abc.csv","w")

    wr=csv.writer(f)

    wr.writerow(l)

    f.close()

#display all records of abc.csv file

def disp():

    f=open("abc.csv","r",newline="\n")

    r=csv.reader(f)

    print(r)

    for i in r:

        print(i)

    f.close()

#Add()

#Append()

#Append()

#disp()

#search()

#delete()

#disp()