替换 用空格或空字符串PHP

好吧,我已经尝试了这些,似乎它们都没有工作,我的示例字符串是

 $text_description="       Hello World! lorel ipsum";

 $text_description= str_replace(" "," ",$text_description);
 $text_description = preg_replace("/&#?[a-z0-9]+;/i"," ",$text_description);
 $text_description=html_entity_decode($text_description);

解决方法:

$text_description="       Hello World! lorel ipsum";
$text_description = str_replace(' ', ' ', $text_description);
echo $text_description;

输出：

Hello World! lorel ipsum