Question

I have a csv file that has like 30,000 rows in it. It also has like 9 columns. In the interest of speeding up the processing of everything I want to reduce the file to the two columns that I need and remove the rest. here is what I have done.

$retardment=1;//17;// 151;  //499;//  991;// 1877
if (($handle = fopen($source, "r")) !== FALSE) {
    $stock_handle = fopen($source_stock, "w+"); 
    $row=0;
    $col=array();
    while (($line = fgetcsv($handle, 100000, ",")) !== FALSE) {
            unset($line[1]);
            unset($line[2]);
            unset($line[3]);
            unset($line[4]);
            unset($line[5]);
            unset($line[6]);
            unset($line[8]);
            unset($line[9]);
        if($row%$retardment<1){
            fputcsv($stock_handle, $line);
        }
            unset($line);
        $row++;
    }
    fclose($handle);
    fclose($stock_handle);
}

I am coping it to a new file and this works… but it seems to be pretty slow. Any ideas on how to make it faster? Thank you for the help.

Cheers -Jeremy

{EDIT}
So far this seems to take just as long. But works just fine

while (($line = fgetcsv($handle, 100000, ",")) !== FALSE) {
    if($row%$retardment<1){
        fputcsv($stock_handle, array($line[0],$line[7]));
    }
    $row++;
}

Answer 1

You could replace those unset() calls with…

$line = array($line[0], $line[7]);

Alternatively, remember that unset() takes multiple arguments…

unset($line[1], $line[2], ...);