Question

i would like to understand how to use the buffer of a read file.

Assuming we have a big file with a list of emails line by line ( delimiter is a classic \n )

now, we want compare each line with each record of a table in our database in a kind of check like line_of_file == table_row.

this is a simple task if you have a normal file, otherwise, if you have a huge file the server usually stop the operation after few minute.

so what’s the best way of doing this kind of stuff with the file buffer?

what i have so far is something like this:

$buffer = file_get_contents('file.txt');
while($row = mysql_fetch_array($result)) {
  if ( preg_match('/'.$email.'/im',$buffer)) {
    echo $row_val;
  }
}

---

$buffer = file_get_contents('file.txt');
$lines = preg_split('/\n/',$buffer); 
//or $lines = explode('\n',$buffer);
while($row = mysql_fetch_array($result)) {
  if ( in_array($email,$lines)) {
    echo $row_val;
  }
}

Answer 1

Like already suggested in my closevotes to your question (hence CW):

You can use SplFileObject which implements Iterator to iterate over a file line by line to save memory. See my answers to

• Least memory intensive way to read a file in PHP and
• How to save memory when reading a file in Php?

for examples.