[php] How to remove line breaks (no characters!) from the string?

This might appear to be a dupe, but rest assured it isn't - I have searched both SO as well as the rest of the web for an answer to my problem and ended up finding the same insufficient "solutions" over and over. Anyhow, here it goes:

I'm saving user input from a textarea to a MySQL database (within a WordPress environment, but that ought not to matter to this problem, I believe). It is later retrieved from the DB to be shown to Admins in the backend of the site. The problem occurs when users submit text with line breaks (i.e. hit the Enter key).

A sample string might look like this:

Dear friends, I just wanted so Hello. How are you guys? I'm fine, thanks!

Greetings,
Bill

There are no end of line characters ("\n", "\r", or the like) in the string.

I am using nl2br() on it to generate HTML output, but that's not enough. The result then is:

Dear friends, I just wanted so Hello. How are you guys? I'm fine, thanks!<br />
<br />
Greetings,<br />
Bill

Which, as far as I understand it, is the expected nl2br() result, as that inserts the tags and isn't supposed to replace the line-breaks in the first place?

However the format I need would be this:

Dear friends, I just wanted so Hello. How are you guys? I'm fine, thanks!<br /><br />Greetings,<br />Bill

If the string had EOL characters such as "\n" in it, I'd hit it with either str_replace() or preg_replace() and be done with it, but I have no clue what needle to feed either of those functions if there ain't no characters there in the first place.

I can manually access the relevant field in the DB, hit Backspace for every linebreak and what I later on want to do with the string works. So I know I need the above format.

str_replace(PHP_EOL, null, $str);

Ben's solution is acceptable, but str_replace() is by far faster than preg_replace()

$buffer = str_replace(array("\r", "\n"), '', $buffer);

Using less CPU power, reduces the world carbon dioxide emissions.

$str = "
Dear friends, I just wanted so Hello. How are you guys? I'm fine, thanks!<br />
<br />
Greetings,<br />
Bill";

echo str_replace(array("\n", "\r"), '', $str);  // echo $str in a single line

It's because nl2br() doesn't remove new lines at all.

Returns string with <br /> or <br> inserted before all newlines (\r\n, \n\r, \n and \r).

Use str_replace instead:

$string = str_replace(array("\r\n", "\r", "\n"), "<br />", $string);

I use 3 lines to do this job, so consider $s as your "stuff"...

$s=str_replace(chr(10),'',$s);
$s=str_replace(chr(13),'',$s);
$s=str_replace("\r\n"),'',$s);

Alternative built-in: trim()

trim — Strip whitespace (or other characters) from the beginning and end of a string
Description ¶
trim ( string $str [, string $character_mask = " \t\n\r\0\x0B" ] ) : string

This function returns a string with whitespace stripped from the beginning and end of str.
Without the second parameter, trim() will strip these characters:

    " " (ASCII 32 (0x20)), an ordinary space.
    "\t" (ASCII 9 (0x09)), a tab.
    "\n" (ASCII 10 (0x0A)), a new line (line feed).
    "\r" (ASCII 13 (0x0D)), a carriage return.
    "\0" (ASCII 0 (0x00)), the NUL-byte.
    "\x0B" (ASCII 11 (0x0B)), a vertical tab.

It's there to remove line breaks from different kinds of text files, but does not handle html.

To work properly also on Windows I'd suggest to use

$buffer = str_replace(array("\r\n", "\r", "\n"), "", $buffer);

"\r\n" - for Windows, "\r" - for Mac and "\n" - for Linux

Something a bit more functional (easy to use anywhere):

function strip_carriage_returns($string)
{
    return str_replace(array("\n\r", "\n", "\r"), '', $string);
}

Using PHP_EOL as the search replacement parameter is also a good idea! Kudos.

You can also use PHP trim

This function returns a string with whitespace stripped from the beginning and end of str. Without the second parameter, trim() will strip these characters:

• " " (ASCII 32 (0x20)), an ordinary space.
• "\t" (ASCII 9 (0x09)), a tab.
• "\n" (ASCII 10 (0x0A)), a new line (line feed).
• "\r" (ASCII 13 (0x0D)), a carriage return.
• "\0" (ASCII 0 (0x00)), the NUL-byte.
• "\x0B" (ASCII 11 (0x0B)), a vertical tab.