Delete multiple Column(headers) in csv in python - python-3.x

Question

Here is my code
import csv
#import pandas as pd
f = open("stu.csv", "a+", newline="")
Smain = csv.writer(f)
Smain.writerow(["Name", "Father Name", "Class", "Admission Number"])
mainrec = []
increas = 1
class1 = open("class-1.csv", "a+", newline="")
stuclas1 = csv.writer(class1)
stuclas1.writerow(["Roll Number", "Name", "Admission Number"])
while True:
nam = input("Enter Student Name - ")
Clas = int(input("Enter Class - "))
Fname = input("Enter Father Name - ")
adm = 100 + increas
lst = [nam, Fname, Clas, adm]
mainrec.append(lst)
if Clas == 1:
stucls1list = []
a1 = 0
rollnum_cla1 = 0 + increas + a1
a1 = 0 + rollnum_cla1
lst1 = [rollnum_cla1, nam, adm]
stucls1list.append(lst1)
for i1 in stucls1list:
stuclas1.writerow(i1)
increas += 1
c = input("Input 'Y' If You Want To Record More, Otherwise Press 'N' - ")
if c == "N":
break
for i in mainrec:
Smain.writerow(i)
# load dataset
#df = pd.read_csv("stu.csv")
# select the rows
# if Name column
# has special characters
#print(df[df.Name.str.contains(r'[Name]')])
# drop the merged selected rows
f.close()
class1.close()
Can anyone tell me how i can delete duplicate header
when i run this program more than 2 time it start duplication header and i dont want to duplicate header again and again please tell me how i can delete that header(column)
stu csv when
i run this program 2 times
Name,Father Name,Class,Admission Number
xyz,xyz,1,101
qwe,qwe,1,102
N,N,1,103
Name,Father Name,Class,Admission Number # this i want to delete
test,test,1,101
you,you,1,102

Answer 1

Here's a way to solve for it.
f = open("stu.csv", "a+", newline="")
f.seek(0)
if len(f.read()) == 0
Smain = csv.writer(f)
Smain.writerow(["Name", "Father Name", "Class", "Admission Number"])
This will check if there is content inside the file. If it has contents, then you already have the header. If there is no content, then you dont have a header. This will determine if you need to write the header to the file.
Here's the sample output when I tried:
First run:
No header #my print statement output
Output file after first run: #the file header written to file
Name,Father Name,Class,Admission Number
Second run:
header found, skipped writing header again #my print statement output
It did not write the output to file again.
Output file on second run:
Name,Father Name,Class,Admission Number
Note here that f.write will move the pointer to the last line by default (since the file is opened in a+ mode)