How to remove row with duplicate value from CSV (PHP)?

Question

PHP

There is an array in php array

$list = array (
              array('', $_POST['subject'], $_POST['time'], $_POST['text'], $_POST['name_html'],''),
          );

And there is a CSV file.
First, I add this array to the end of the file in array and I get one new line with the data received from the POST request.

$list = array (
              array('', $_POST['subject'], $_POST['time'], $_POST['text'], $_POST['name_html'],''),
          );

          $fp = fopen('db/cards.csv', 'a');

          foreach ($list as $fields) {
              fputcsv($fp, $fields);
          }

          fclose($fp);

After that, I need to go through the same file and remove from it the first (if you go from top to bottom) line that appears, where the same $_POST['subject'] will be mentioned. Accordingly, I just want to remove the old $_POST['subject'] value from the database. And I don't know how to do it.

All code

Answer 1

i just want to remove old $_POST['subject'] value from db

Dear Nikita from 7"B", I don't want to seem rude, but for this task it's better to use a real database (at least PDO + SQLite), and not emulate a database on csv files.
And if on the merits of the question, then something like this is done

<?php
$list = [];
if(($handle = fopen("db/cards.csv", "r")) !== false)
{
    while(($data = fgetcsv($handle, 1000, ",")) !== false)
    {
        $subject = $data[1];
        $list[$subject] = $data; //<--- ключевой момент
    }
    fclose($handle);
}

//теперь в $list только строки с уникальным $subject
print_r($list);

//перезаписываем csv данными из $list
//тут ваш код