PHP-如何有效读取大型远程文件并循环使用缓冲区 [英] PHP - how to read big remote files efficiently and use buffer in loop
问题描述
我想了解如何使用读取文件的缓冲区。
i would like to understand how to use the buffer of a read file.
假设我们有一个大文件，其中逐行列出了电子邮件列表（定界符为经典 \n ）
Assuming we have a big file with a list of emails line by line ( delimiter is a classic \n )
现在，我们想将每一行与数据库中表的每个记录进行比较以类似 line_of_file == table_row 这样的检查方式。
now, we want compare each line with each record of a table in our database in a kind of check like line_of_file == table_row.
如果您有普通文件，这是一个简单的任务，否则，如果文件很大，服务器通常会在几分钟后停止操作。
this is a simple task if you have a normal file, otherwise, if you have a huge file the server usually stop the operation after few minute.
那么用文件缓冲区执行这种操作的最佳方法是什么？
so what's the best way of doing this kind of stuff with the file buffer?
到目前为止，我的情况是这样的：
what i have so far is something like this:
$buffer = file_get_contents('file.txt');
while($row = mysql_fetch_array($result)) {
if ( preg_match('/'.$email.'/im',$buffer)) {
echo $row_val;
}
}
$buffer = file_get_contents('file.txt');
$lines = preg_split('/\n/',$buffer);
//or $lines = explode('\n',$buffer);
while($row = mysql_fetch_array($result)) {
if ( in_array($email,$lines)) {
echo $row_val;
}
}
推荐答案
在我对您的问题的投票中（因此CW）已经建议过：
Like already suggested in my closevotes to your question (hence CW):
您可以使用 SplFileObject ，它实现了Iterator来逐行迭代文件以节省内存。看到我的答案
You can use SplFileObject which implements Iterator to iterate over a file line by line to save memory. See my answers to
- Least memory intensive way to read a file in PHP and
- How to save memory when reading a file in Php?
例如。
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