Removing blank lines from a textarea's output

问题

I get data from a textarea where a user has to enter a name one on each line. That data later gets split at the carriage return. Sometimes a user may add blank lines intentionally. How can I detect these lines and delete them? I'm using PHP. I dont mind using a regexp or anything else.

Incorrect Data

Matthew
Mark
Luke

John

James

Correct Data (Note blank lines removed)

Matthew
Mark
Luke
John
James

回答1:

Using regex to eliminate blank lines before exploding (works well for any number of consecutive blank lines, also see next snippet):

$text = preg_replace('/\n+/', "\n", trim($_POST['textarea']));

Splitting with a regex:

$lines = preg_split('/\n+/', trim($_POST['textarea']));
$text = implode("\n", $lines);

Splitting without a regex:

$lines = array_filter(explode("\n", trim($_POST['textarea'])));
$text = implode("\n", $lines);

Just feeling a tad creative today, pick your poison :)

回答2:

A simple string replace should do the trick, I believe.

str_replace("\r\n\r\n", "\r\n", $text);

回答3:

After splitting your input, loop the array searching for empty lines:

$lines = explode("\n", $_POST['your_textarea']);
foreach ($lines as $k=>$v) if(empty($v)) unset($lines[$k]);

You could even look for lines containing just spaces to also delete them:

$lines = explode("\n", $_POST['your_textarea']);
foreach ($lines as $k=>$v) if(empty(trim($v))) unset($lines[$k]);

(Both code snippets are untested)

NOTE: Be careful when splitting by line breaks (I splitted them by \n, but could be \r\n if the client browser runs on Windows).

来源：https://stackoverflow.com/questions/4214685/removing-blank-lines-from-a-textareas-output