cleaning mysql text from line breaks

Question

How would you go about removing extra line breaks for example:

text text text


text text

And i would like it to be this way

text text
text

i am already using nl2br($desc) in order for the line breaks to appear at all now how to i limit them to 1

Answer 1

Before using nl2br() replace all sequences of carriage return or new line characters with a single newline:

$result = preg_replace('/[\r\n]+/', "\n", $desc);

See it working online: ideone

Answer 2

在nl2br()之后：

$desc = preg_replace('#(<br[ ]?[\/]?>[\r\n]*)+#','<br/>',$desc);