fseek()按行而不是字节? [英] fseek() by line, not bytes?

问题描述

我有一个脚本，可以逐行解析大文件.当遇到无法处理的错误时，它将停止，并通知我们已解析的最后一行.

I have a script that parses large files line by line. When it encounters an error that it can't handle, it stops, notifying us of the last line parsed.

这真的是查找文件中特定行的最佳/唯一方法吗? (在我的情况下，fseek()不可用.)

Is this really the best / only way to seek to a specific line in a file? (fseek() is not usable in my case.)

<?php

for ($i = 0; $i < 100000; $i++)
    fgets($fp); // just discard this

我使用它没有问题，它足够快-感觉有点脏.据我对底层代码的了解，我认为没有更好的方法可以做到这一点.

I don't have a problem using this, it is fast enough - it just feels a bit dirty. From what I know about the underlying code, I don't imagine there is a better way to do this.

推荐答案

查找文件中特定行的简单方法是使用 SplFileObject 类，该类支持查找行号( seek() )或字节偏移量( fseek() ).

An easy way to seek to a specific line in a file is to use the SplFileObject class, which supports seeking to a line number (seek()) or byte offset (fseek()).

$file = new SplFileObject('myfile.txt');
$file->seek(9999);     // Seek to line no. 10,000
echo $file->current(); // Print contents of that line

在后台，seek()会执行您的PHP代码(C语言代码除外).

In the background, seek() just does what your PHP code did (except, in C code).

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