How can I get at the matches when using preg_replace in PHP?
You need to put the pattern in parentheses /([A-Z])/, like this:
preg_replace("/([A-Z])/", "<span class=\"initial\">$1</span>", $str)
\0 will also match the entire matched expression without doing an explicit capture using parenthesis.
preg_replace("/[A-Z]/", "<span class=\"initial\">\\0</span>", $str)As always, you can go to php.net/preg_replace or php.net/<whatever search term> to search the documentation quickly. Quoth the documentation:
\0 or $0 refers to the text matched by the whole pattern.
From the preg_replace documentation on php.net:
replacement may contain references of the form \n or (since PHP 4.0.4) $n, with the latter form being the preferred one. Every such reference will be replaced by the text captured by the n'th parenthesized pattern.
See Flubba's example.