Problem with replacing garbled characters under Mac OS X

God, let’s see why the code is garbled?

It hasn’t been solved for several years
Environment: under mac OS I have tested the same problem on both), please help!

$string = "短标题";
$o = preg_replace(array('/\s+/'), array("->"), $string);
echo $string , ' ===> ' , $o;

The screenshot below is allowed, and the garbled code appears.

Reply content:

God, let’s see why the code is garbled?

It hasn’t been solved for several years
Environment: under mac OS I have tested the same problem on both), please help!

$string = "短标题";
$o = preg_replace(array('/\s+/'), array("->"), $string);
echo $string , ' ===> ' , $o;

The screenshot below is allowed, and the garbled code appears.

Add a line in front header('Content-type: text/html; charset=utf-8'); and try it.

Looks like there’s no problem. .