preg_replace总是提供与$ 1相同页面的链接

Question

I am using preg_replace in PHP. When i use this code line:

echo nl2br(preg_replace("(http://.+) ", "<a href='$1'>[link]</a>", $row['description']));

It echoes "<a href=''>[link]</a>". Here is the "description": http://www.youtube.com/watch?v=JDrnz8ZZtUE
What is wrong with this? (I also included the space in the description)

Answer 1

That's because you didn't specify delimiters. PHP will assume the () to be delimiters, thus eliminating your capture group.

"~(http://.+)~"