PHP Regular Expression to find pattern but only replace one character

Question

I'm converting a PDF to text using xpdf pdf2text and it works great except for one thing: it converts paragraph symbols (¶) into the number 8. I need to find a way to get to everything with the pattern of:

preg_match_all('/\b8\d{1,2}-/', 'text');

but only replace the "8" from that pattern. I've tried saving the matches into an array, but them how do I re-insert them into the text where they belong?

Ideally, the paragraph tag would just convert properly, but I've tried several different encodings with no success; I think some of the pdf's have embedded fonts.

Any ideas on how I could replace just the "8" in that pattern? I can't just replace all 8's because the page or chapter of the article being referenced may be 8; but there is no danger of the paragraph being 80-something (which is why I check for a digit after the 8).

Thanks.

Answer 1

捕获组中其余模式并将其放回原位：

$str = preg_replace('/\b8(\d{1,2}-)/', 'replacement$1', $str);