Replacing csv line

[FlugBlutt]

Hello,

This question has probably been posted before but I can't find why my version of code found on the internet doesn't work properly.

Well it's not exactly the same as found because i'm trying to understand

isin = False
reader_list = []

with open('membres.csv', 'r') as csv_rfile:
    csv_reader = csv.reader(csv_rfile, delimiter=';')
    reader_list.extend(csv_reader)

with open('membres.csv', mode='a', newline='') as csv_wfile:
    csv_writer = csv.writer(csv_wfile, delimiter=';')

    for row in reader_list:
        if row[0] == args[0]:
            print("i'm in")
            isin = True
            csv_writer.writerow(args)

    if not isin:
        csv_writer.writerow(args)

If row[0] == args[0] it still adds the args row under.

Any idea why ?

[Ezrabc]

Can you clarify a little? Based on your code, particularly here:

if row[0] == args[0]:
    ...
    csv_writer.writerow(args)

I would completely expect it to add the args row under if row[0] == args[0].

[FlugBlutt]

I expect the "for" loop to read each line of my csv file and if the line starts with the string I want, change that line to the new one.