你可以为文件使用一个面向对象的接口类——SplFileObject http://php.net/manual/en/splfileobject.fgets.php (PHP 5 >= 5.1.0)

<?php

$file = new SplFileObject("file.txt");

// Loop until we reach the end of the file.
while (!$file->eof()) {
    // Echo one line from the file.
    echo $file->fgets();
}

// Unset the file to call __destruct(), closing the file handle.
$file = null;

函数读取数组返回

function read_file($filename = ''){
    $buffer = array();
    $source_file = fopen( $filename, "r" ) or die("Couldn't open $filename");
    while (!feof($source_file)) {
        $buffer[] = fread($source_file, 4096);  // use a buffer of 4KB
    }
    return $buffer;
}

foreach (new SplFileObject(__FILE__) as $line) {
    echo $line;
}

有一个file()函数返回文件中包含的行数组。

foreach(file('myfile.txt') as $line) {
   echo $line. "\n";
}

小心使用'while(!feof……Fgets()的东西，Fgets可以得到一个错误(返回false)和永远循环而不到达文件的结束。Codaddict是最接近正确的，但当你的'while fgets'循环结束时，检查feof;如果不是真的，那么你就出错了。

这就是我如何处理非常大的文件(测试高达100G)。它比fgets()快

$block =1024*1024;//1MB or counld be any higher than HDD block_size*2
if ($fh = fopen("file.txt", "r")) { 
    $left='';
    while (!feof($fh)) {// read the file
       $temp = fread($fh, $block);  
       $fgetslines = explode("\n",$temp);
       $fgetslines[0]=$left.$fgetslines[0];
       if(!feof($fh) )$left = array_pop($lines);           
       foreach ($fgetslines as $k => $line) {
           //do smth with $line
        }
     }
}
fclose($fh);