Why Am I Getting Trailing Newlines When Writing to a File in PHP?

Line Feed Woes in PHP: Overcoming the Trailing Newline

When writing to a file in PHP using fwrite() with 'w' mode, it's common for unexpected newline characters to append to the output. This was the case in the provided code, where 'n' was intended to create line breaks but instead appeared as a string.

The n Dilemma

The reason behind this peculiar behavior lies in the escape sequence used. By default, single-quoted strings treat 'n' as a literal backslash followed by the letter 'n', not a newline character. To rectify this, it's necessary to use double-quoted strings and escape the newline character properly using "n".

Windows and Unix Line Endings

Another aspect to consider is the line ending character. Different operating systems utilize different conventions for line endings:

• Windows: "rn" (carriage return followed by newline)
• Unix-based systems (including Linux and macOS): "n" (newline only)

To ensure proper line ending handling, it's recommended to open the file in binary mode, which allows writing raw data without any line ending conversion. This involves using 'wb' as the second parameter to fopen().

Updated Code:

By implementing these fixes, the modified code below successfully writes each gem ID on a new line without any extraneous characters:

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

The above is the detailed content of Why Am I Getting Trailing Newlines When Writing to a File in PHP?. For more information, please follow other related articles on the PHP Chinese website!