php file_put_contents ...可以在开头附加吗？
<?php
$file = 'people.txt';
// The new person to add to the file
$person = "John Smith\n";
// Write the contents to the file,
// using the FILE_APPEND flag to append the content to the end of the file
// and the LOCK_EX flag to prevent anyone else writing to the file at the same time
file_put_contents($file, $person, FILE_APPEND | LOCK_EX);
?>
这会将内容附加到文件末尾。我想在文件的开头写入最新的内容。
<?php
$file = 'people.txt';
// The new person to add to the file
$person = "John Smith\n";
// Write the contents to the file,
// using the FILE_APPEND flag to append the content to the end of the file
// and the LOCK_EX flag to prevent anyone else writing to the file at the same time
file_put_contents($file, $person, FILE_APPEND | LOCK_EX);
?>
This will append the content at the end of the file. i want to write newest at the beginning of the file.
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正如手册页所示，没有用于预先添加数据的标志。
您需要首先使用
file_get_contents()读取整个文件，在前面添加值，然后保存整个字符串。As the manual page shows, there is no flag to prepend data.
You will need to read the whole file using
file_get_contents()first, prepend the value, and save the whole string.在文件开头写入可能会给文件系统和硬盘带来一些不必要的开销。
作为解决方案，您必须读取内存中的整个文件，写入要添加的新内容，然后写入旧内容。对于大文件，这需要时间和内存（这取决于您的实际工作负载，但一般来说，它很慢）。
正常附加（在末尾）然后向后读取文件是否是一个可行的解决方案？这将导致写入速度更快，但读取速度更慢。这基本上取决于你的工作量:)
writing at the beginning of a file might incur some unnecessary overhead on the file-system and the hard-disk.
As a solution, you would have to read the entire file in-memory, write the new content you want added, and then write the old content. This takes time and memory for large files(it depends on the actual workload you have, but as a general rule, its slow).
Would appending normally(at the end) and then reading the file backwards would be a viable solution? This would lead to faster writes, but slower reads. It basically depends on your workload:)
如果您想使用
file_put_contents，您将无法选择，您需要读取/连接/写入。You won't have the choice if you want to use
file_put_contents, you'll need to read / contatenate / write.