PHP is a regular match for multiple results, randomly replacing one of the results

PHP matches multiple results in regular, randomly replacing one of the results

With regular match characters, if all substitutions are simple, using preg_replace is fine. But I'm going to have to randomly replace one of the results of the multiple matches I've got, which is a bit of a hassle. I wrote a function to solve, do not know there is no other better way. Example "I have a Dream". I have a dream. I have a dream. I have a dream. "Matching '/i/'. There are 4 matching results in the above string, so I just randomly replace one of them. I replace it with hell.

My code is as follows:

Regular handler function Rand_replace_callback ($matches) {global $g _rand_replace_num, $g _rand_replace_index, $g _rand_    REPLACE_STR;    $g _rand_replace_index++;    if ($g _rand_replace_num== $g _rand_replace_index) {return $g _rand_replace_str;      }else {return $matches [0]; }//Random Regular substitution function if there are multiple matched cells, randomly replace one of them. Note that global $g _rand_replace_num, $g _rand_replace_index, $g _rand_replace_str; These three global variables, and do not conflict with it//depend on a regular handler function to record the total number of matching units, Take a random value in the total range, and then treat it in the regular processing function. function Rand_preg_replace ($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 matched cells $g _rand_replace_num = Mt_rand (1, $find _count);  A collection that conforms to the regular search criteria $g _rand_replace_index = 0;    The index $g _rand_replace_str = $t _g_rand_replace_str in the actual substitution process; echo "Now found a match with {$find _count}
";    $ss =preg_replace_callback ($pattern, "Rand_replace_callback", $string); return $SS;} $string = "I have a dream. I have a dream. I have a dream. I have a dream. "; echo rand_preg_replace ('/i/', "hell", $string);

Expand thinking, I want to reduce the first result is replaced by the concept of what to do? In some cases, the first one is replaced not very well, only a small amount of the result is the first one to be replaced.

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