str_ireplace() with keeping of case

Question

How can I use str_ireplace (or something similar) to replace some text for formatting and then return it with the same caps?

Example:

$original="The quick red fox jumps over the lazy brown dog.";
$find="thE";

print str_ireplace($find,'<b>'.$find.'</b>',$original);

That will output: thE quick red fox jumps over the lazy brown dog.

I want it to keep the original case and only apply the formatting, in this example, bold text.

Thank you.

Answer 1

$original = "The quick red fox jumps over the lazy brown dog.";
$new = preg_replace("/the/i", "<b>\$0</b>", $original);

gives "The quick red fox jumps over the lazy brown dog." If you want to match specific words, you can add word boundaries: preg_replace('/\bthe\b/i', ....

If you want to parameterize the replacement, you can use preg_quote:

 preg_replace('/\b' . preg_quote($word, "/") . '\b/i', "<b>\$0</b>", $original);