Writing a new line to file in PHP (line feed)

问题

My code:

$i = 0;
$file = fopen(\'ids.txt\', \'w\');
foreach ($gemList as $gem)
{
    fwrite($file, $gem->getAttribute(\'id\') . \'\\n\');
    $gemIDs[$i] = $gem->getAttribute(\'id\');
    $i++;
}
fclose($file);

For some reason, it\'s writing \\n as a string, so the file looks like this:

40119\\n40122\\n40120\\n42155\\n36925\\n45881\\n42145\\n45880

From Google\'ing it tells me to use \\r\\n, but \\r is a carriage return which doesn\'t seem to be what I want to do. I just want the file to look like this:

Thanks.

回答1:

Replace '\n' with "\n". The escape sequence is not recognized when you use '.

See the manual.

For the question of how to write line endings, see the note here. Basically, different operating systems have different conventions for line endings. Windows uses "\r\n", unix based operating systems use "\n". You should stick to one convention (I'd chose "\n") and open your file in binary mode (fopen should get "wb", not "w").

回答2:

Use PHP_EOL which outputs \r\n or \n depending on the OS.

回答3:

PHP_EOL is a predefined constant in PHP since PHP 4.3.10 and PHP 5.0.2. See the manual posting:

Using this will save you extra coding on cross platform developments.

IE.

$data = 'some data'.PHP_EOL;
$fp = fopen('somefile', 'a');
fwrite($fp, $data);

If you looped through this twice you would see in 'somefile':

some data
some data

回答4:

You can also use file_put_contents():

file_put_contents('ids.txt', implode("\n", $gemList) . "\n", FILE_APPEND);

来源：https://stackoverflow.com/questions/3066421/writing-a-new-line-to-file-in-php-line-feed

标签

php

newline

fopen

fwrite

linefeed