Member Avatar for SoftP

Hello Developers,

How to Delete And Update particular row of CSV file in php.

<a href=""></a>

Thanks & Regards,
Dinesh Thakur

Edited by SoftP
  • 2 Contributors
  • 1 Reply
  • 2K Views
  • 5 Hours Discussion Span
  • Latest Post Latest Post by Traevel

Dani AI

Generated

CSV is not a database. You cannot reliably change a single row in-place. The safe pattern (as already hinted) is: read each row, decide whether to update or skip it, write the result to a temporary file, then replace the original. Use the CSV helpers so quoted commas and newlines are handled correctly.

<?php
function csv_update_or_delete($file, $keyColumn, $keyValue, array $updates = null) {
    $in = fopen($file, 'r');
    if (!$in || !flock($in, LOCK_EX)) return false;

    $tmp = $file . '.tmp';
    $out = fopen($tmp, 'w');
    if (!$out) { flock($in, LOCK_UN); fclose($in); return false; }

    // assume header row; use names if provided, else pass a numeric index for $keyColumn
    $header = fgetcsv($in);
    $map = array_flip($header);
    $keyIndex = is_int($keyColumn) ? $keyColumn : $map[$keyColumn];

    fputcsv($out, $header);
    $changed = false;

    while (($row = fgetcsv($in)) !== false) {
        $isMatch = isset($row[$keyIndex]) && (string)$row[$keyIndex] === (string)$keyValue;

        if ($isMatch && is_array($updates)) {
            foreach ($updates as $col => $val) {
                $i = is_int($col) ? $col : ($map[$col] ?? null);
                if ($i !== null) $row[$i] = $val;
            }
            fputcsv($out, $row);         // update
            $changed = true;
        } elseif ($isMatch && $updates === null) {
            $changed = true;              // delete (skip writing)
        } else {
            fputcsv($out, $row);          // keep
        }
    }

    fflush($out); fclose($out); flock($in, LOCK_UN); fclose($in);
    if ($changed) return rename($tmp, $file);
    unlink($tmp); return false;
}

// examples:
// update row with id=42
csv_update_or_delete('data.csv', 'id', '42', ['email' => 'new@example.com']);
// delete row with id=42
csv_update_or_delete('data.csv', 'id', '42');

Notes:

  • Create the temp file next to the original so the final rename is straightforward and fast. Ensure the destination is writable.
  • Always use the CSV functions (fgetcsv, fputcsv) rather than explode.
  • If multiple scripts may write, have all of them honor a lock with flock before you replace the file with rename.
Member Avatar for Traevel

But how will anyone know it was updated if you delete it first?

In case you meant delete or update, then

For update:

  1. Read the file line by line
  2. Manipulate the line
  3. Write back to file

For deletion:

  1. Read the file line by line
  2. Store the lines you want to keep
  3. Write those back to file

super secret shortcut for the above steps

In all seriousness though, seeing as your file isn't very big you could probably store every line in an array, manipulate/delete those and write each value back to a file, it's nothing fancy and plenty of information already exists. Especially since it's a very general question with hardly any specifics or prework.

Be a part of the DaniWeb community

We're a friendly, industry-focused community of developers, IT pros, digital marketers, and technology enthusiasts meeting, networking, learning, and sharing knowledge.