Reading columns in a csv file but getting wrong output

Okay managed to figure it out for myself. So the new code is as follows:

import sys, select, os, csv
from os import system

with open(input("\nInput file name with .csv extension: "), 'r', newline = '') as f:

    fileDir = os.path.dirname(os.path.realpath('__file__'))
    reader = csv.reader(f, delimiter = '\t')
    header_row = next(reader)
    print('\t'.join(header_row))
    # Can use the 2 lines below to check indices of headers
    # name = [0], age = [1], sex = [2]
    # for index, column_header in enumerate(header_row):
    #   print(index, column_header)

    name_l = []
    age_l = []
    sex_l = []

    total_tickets = 0
    
    for row in reader:
        name = str(row[0])
        name_l.append(name)
        age = str(row[1])
        age_l.append(age)
        sex = str(row[2])
        sex_l.append(sex)
        total_tickets += 1

        print('\t'.join(row))
        
    print("\nTotal Tickets: ", total_tickets)

I see you going through some steps that are unnecessary, and even caused the confusion that lead to your original problem.

Here's a minimal example that asks for user input, reads in and counts the rows, and then writes everything out:

import csv
import sys

fname = input('\nInput file name with .tsv extension: ')

total_tickets = 0

rows = []
with open(fname, newline='') as f:
    reader = csv.reader(f, delimiter='\t')
    rows.append(next(reader))  # read and add header

    for row in reader:
        rows.append(row)
        total_tickets += 1

writer = csv.writer(sys.stdout, delimiter='\t')
writer.writerows(rows)

print(f'\nTotal tickets: {total_tickets}')

Here's me running this:

% python3 so.py

Input file name with .tsv extension: so.tsv
Name    Age     Sex
as      12      f
qw      13      m

Total tickets: 2

The big takeaway is that there are two steps you can completely avoid:

• string-converting all the cells is redundant, it's text coming in and text going out; if you just want to pass the data through, just append the whole row to rows, because...

• writing the rows manually can be tricky as you saw, and csv.writer can do it for you

I reviewed the Python docs answering this, and I can see that there is no complete example where tabulated data is read in, processed, and then written out, so I can see how you got the idea to write your rows yourself.

Also, I'd never seen newline='', and was scratching my head till I saw the docs mention thats the way to do it... learned something new, thanks!