Use regular expressions to match multiple results in PHP and randomly replace one of the results_PHP Tutorial

Use regular matching characters. If it is very simple to replace all, just use preg_replace. But now I need to randomly replace one of the multiple successful matching results, which is a bit troublesome. I wrote a function myself to solve it. I don’t know if there is any other better way. Example "I have a dream. I have a dream. I have a dream. I have a dream." Matches the expression '/i/'. There are 4 matching results in the above string, and I just need to randomly replace one of them. Replace i with hell.

} //Random regular replacement function If there are multiple matching units, randomly replace one of them. //Pay attention to global $g_rand_replace_num, $g_rand_replace_index, $g_rand_replace_str; these three global variables should not conflict with other ones //Depends on a regular processing function to record the total number of matching units, take a random value within the range of the total number, and process it if it is judged to be equal in the regular processing function. function rand_preg_replace($pattern, $t_g_rand_replace_str, $string) { global $g_rand_replace_num, $g_rand_replace_index, $g_rand_replace_str; preg_match_all($pattern, $string, $out);$find_count = count($out[0]); //Total number of matching units $g_rand_replace_num = mt_rand(1, $find_count); //A collection that meets regular search conditions $g_rand_replace_index = 0; //index during the actual replacement process $g_rand_replace_str = $t_g_rand_replace_str; echo "Now there are {$find_count} matches found
"; $ss=preg_replace_callback($pattern,"rand_replace_callback",$string); return $ss; www.2cto.com} $string = "I have a dream. I have a dream. I have a dream. I have a dream."; echo rand_preg_replace('/I/', "hell", $string); Expanding thinking, I want to reduce the concept of the first result being replaced. What should I do? There are cases where it's not good to be the first to be replaced, and only a small number of results are needed to be the first to be replaced.