PHP Find String in CSV file

Question

I've got a large flat file of usernames and emails in the following format:

"username", "email"
"username", "email"
"username", "email"

etc...

I need to take the email and search for the username, but for some reason it will not return a result. It works if I search opposite.

$string = "[email protected]";
$filename = "user_email.txt";
        $h = fopen("$filename","r");
        $flag=0;

        while (!feof ($h)) {
            $buffer = fgets($h);
            $thisarray = split(",", $buffer);

            if ($string == str_replace('"','', $thisarray[1])) { 
                $i = 1;
                $i++;
                echo '<td bgcolor="#CCFFCC"><b style="color: maroon">' . str_replace('"','',$thisarray[0]). '</b></td>';

                }   

Any ideas? Thanks!

Answer 1

As per reko_t's suggestion: Use fgetcsv to read individual lines of csv into arrays, until you find one where the second element matches your search term. The first element then is the username. Something like:

<?php
function find_user($filename, $email) {
    $f = fopen($filename, "r");
    $result = false;
    while ($row = fgetcsv($f)) {
        if ($row[1] == $email) {
            $result = $row[0];
            break;
        }
    }
    fclose($f);
    return $result;
}

Answer 2

I truly believe that all examples in other answers works!
But all they are slow, because all of them travers each line in csv file...
I have another example how to find desired string:

$command = sprintf("grep '%s,%s' -Er %s", $userName, $email, $file);
$result = `$command`;

Yes it some kind of dark matter, but it really works and it really fast!