哪里在Regex中放置结尾定界符？

Question

Im quite terrible at regex! can you guys show me where to put the ending delimiter in this piece of code?

$data = preg_replace("/ href=\"\/i", " href=\"{$domain}/", $data);
$data = preg_replace("/ src=\"\/i", " href=\"{$domain}/", $data);

Answer 1

The syntax is as follows:

preg_replace("/PATTERN/FLAGS", "Replace String", $subject);

As you can see, the delimiters are around a pattern , so in your case, your delimiters are in place.

However, you also placed a delimiter in the replace string argument, which you shouldn't have. You also need to escape characters like the backslash \\ . So the correct form would be:

$data = preg_replace("/ href=\"\\/i", " href=\"{$domain}\\", $data);
$data = preg_replace("/ src=\"\\/i", " href=\"{$domain}\\", $data);

That code will replace any instance of href="\\ with href="DOMAIN\\ .

However, for that particular piece of replacement, RegEx is not necessary. You could use a simple str_replace() :

$data = str_replace('href="\\', "href=\"{$domain}\\", $data);
$data = str_replace('src="\\', "src=\"{$domain}\\", $data);