php - highlight the word in the string, if it contains the keyword

Question

how write the script, which menchion the whole word, if it contain the keyword? example: keyword "fun", string - the bird is funny, result - the bird is * funny*. i do the following

     $str = "my bird is funny";
     $keyword = "fun";
     $str = preg_replace("/($keyword)/i","<b>$1</b>",$str);

but it menshions only keyword. my bird is funny

Answer 1

Try this:

preg_replace("/w*?$keywordw*/i", "<b>$0</b>", $str)

w*? matches any word characters before the keyword (as least as possible) and w* any word characters after the keyword.

And I recommend you to use preg_quote to escape the keyword:

preg_replace("/w*?".preg_quote($keyword)."w*/i", "<b>$0</b>", $str)

For Unicode support, use the u flag and p{L} instead of w:

preg_replace("/p{L}*?".preg_quote($keyword)."p{L}*/ui", "<b>$0</b>", $str)