How To Delete The Top 100 Rows From a CSV File With PHP

Question

I have a php script running on a regular basis that processes the top 100 rows of a CSV file. When it is done I want it to delete the processed rows from the CSV file.

I

Answer 1

Here is php code for that:

$input = explode("\n", file_get_contents("file.csv"));
foreach ($input as $line) {
 // process all lines.
}

// This function removes first 100 elements.
// More info:
// http://php.net/manual/en/function.array-slice.php
$output = array_slice($input, 100);
file_put_contents("out.csv", implode("\n", $output));

Note, if csv file contains header you have to remove first element from array $input.

Answer 2

I used this script in the passed written by Joby Joseph:

function csv_delete_rows($filename=NULL, $startrow=0, $endrow=0, $inner=true) {
$status = 0;
//check if file exists
if (file_exists($filename)) {
    //end execution for invalid startrow or endrow
    if ($startrow < 0 || $endrow < 0 || $startrow > 0 && $endrow > 0 && $startrow > $endrow) {
        die('Invalid startrow or endrow value');
    }
    $updatedcsv = array();
    $count = 0;
    //open file to read contents
    $fp = fopen($filename, "r");
    //loop to read through csv contents
    while ($csvcontents = fgetcsv($fp)) {
        $count++;
        if ($startrow > 0 && $endrow > 0) {
            //delete rows inside startrow and endrow
            if ($inner) {
                $status = 1;
                if ($count >= $startrow && $count <= $endrow)
                    continue;
                array_push($updatedcsv, implode(',', $csvcontents));
            }
            //delete rows outside startrow and endrow
            else {
                $status = 2;
                if ($count < $startrow || $count > $endrow)
                    continue;
                array_push($updatedcsv, implode(',', $csvcontents));
            }
        }
        else if ($startrow == 0 && $endrow > 0) {
            $status = 3;
            if ($count <= $endrow)
                continue;
            array_push($updatedcsv, implode(',', $csvcontents));
        }
        else if ($endrow == 0 && $startrow > 0) {
            $status = 4;
            if ($count >= $startrow)
                continue;
            array_push($updatedcsv, implode(',', $csvcontents));
        }
        else if ($startrow == 0 && $endrow == 0) {
            $status = 5;
        } else {
            $status = 6;
        }
    }//end while
    if ($status < 5) {
        $finalcsvfile = implode("\n", $updatedcsv);
        fclose($fp);
        $fp = fopen($filename, "w");
        fwrite($fp, $finalcsvfile);
    }
    fclose($fp);
    return $status;
} else {
    die('File does not exist');
}
}

The function accepts 4 parameters:

1. filename (string): Path to csv file. Eg: myfile.csv

2. startRow (int): First row in delete area

3. endRow (int): Last row in delete area

4. inner (boolean): decide whether rows deleted are from inner area or outer area

Now Let us consider various cases. I have a csv file with me named ‘test.csv’. Here is the screenshot of the same.

Example 1:

$status = csv_delete_rows('test.csv', 3, 5, true);

will delete the red part of:

Example 2:

$status = csv_delete_rows('test.csv', 3, 5, false);

will delete the red part of:

Example 3: Like in your situation, if you want to delete the first 100 rows, use this:

$status = csv_delete_rows('test.csv', 0, 100);