How can I get at the matches when using preg_replace in PHP?

Question

I am trying to grab the capital letters of a couple of words and wrap them in span tags. I am using preg_replace for extract and wrapping purposes, but it\'s not outputting

Answer 1

\0 will also match the entire matched expression without doing an explicit capture using parenthesis.

preg_replace("/[A-Z]/", "\\0", $str)

As always, you can go to php.net/preg_replace or php.net/ to search the documentation quickly. Quoth the documentation:

\0 or $0 refers to the text matched by the whole pattern.