php 文件中随机取出一条数据四种方法

<?php
//第一种方法：
$line = getrandline1('test.txt');
function getrandline1($filename) {
    $linenum = 0;
    $fh = fopen($filename, 'r');
    while (!feof($fh)) {
        if ($rowcontents = fgets($fh)) {
            $linenum++;
            $contens[] = $rowcontents;
        }
    }
    $randline = mt_rand(0, $linenum - 1);
    $line = $contens[$randline];
    fclose($fh);
    return $line;
}
//第二种方法：
$line = getrandline2('test.txt');
function getrandline2($filename) {
    $contents = file('test.txt');
    $linenum = count($contents);
    $randline = mt_rand(0, $linenum - 1);
    $line = $contents[$randline];
    return $line;
}
//第三种方法：
$line = getrandline3('test.txt');
function getrandline3($filename) {
    $contents = file('test.txt');
    shuffle($contents);
    return $contents[0];
}
//第四种方法：
$line = getrandline4('test.txt');
function getrandline4($filename) {
    $linenum = 0;
    $fh = fopen($filename, 'r');
    while (!feof($fh)) {
        if ($linecontents = fgets($fh)) {
            $linenum++;
            $randint = (mt_rand(1, 1000000 * $linenum) - 1) / 1000000);
            if ($randint < 1) {
                $line = $linecontents;
            }
        }
    }
    fclose($fh);
    return $line;
}
?>