Least memory intensive way to read a file in PHP

Question

I am reading a file containing around 50k lines using the file() function in Php. However, its giving a out of memory error since the contents of the file are stored in the memory as an array. Is there any other way?

Also, the lengths of the lines stored are variable.

Here's the code. Also the file is 700kB not mB.

private static function readScoreFile($scoreFile)
{
    $file = file($scoreFile);
    $relations = array();

    for($i = 1; $i < count($file); $i++)
    {
        $relation = explode("",trim($file[$i]));
        $relation = array(
                        'pwId_1' => $relation[0],
                        'pwId_2' => $relation[1],
                        'score' => $relation[2],
                        );
        if($relation['score'] > 0)
        {
            $relations[] = $relation;
        }
    }

    unset($file);
    return $relations;
}

Answer 1

Use fopen, fread and fclose to read a file sequentially:

$handle = fopen($filename, 'r');
if ($handle) {
    while (!feof($handle)) {
        echo fread($handle, 8192);
    }
    fclose($handle);
}