HTML line break in PHP string?

Question

In Wordpress editor, following code is kind of different to me:

case #1

this is a test 

case #2

this is a test
 

The first case will add a space after the sentence, and the #2 case will leave an empty line under the sentence.

Now I am writing a PHP that will include html code in a PHP string,

$post_content = "...."

How to distinguish the two cases above in this $post_content variable?

If I write

$post_content += "this is a test";
$post_content += "&nbsp";

It's the fist case, how to write the #2 case?

Answer 1

换行符用“ \\ n”表示：

$post_content += "this is a test\\n ";

Answer 2

$post_content += "this is a test\n";
$post_content += "&nbsp";

Answer 3

The difference is a newline. You denote it with \\n In PHP you do it like this

$str = "This is a string.\nThis is the second line.";

In your case

$post_content = "this is a test\n&nbsp";