PHP：如何在随机位置的字符串中添加随机字符

Question

How can i add a single random character (0-9 or a-z or - or _) at a random place in a string.

I can get the random position by following:

$random_position = rand(0,5);

Now How can i get a random number ( 0 to 9 ) OR random character (a to z) OR (-) OR (_)

and finally how i can add character to the above string in the above random position.

For example following is string:

$string = "abc123";
$random_position = 2;
$random_char = "_";

the new string should be:

"a_bc123"

Answer 1

$string = "abc123";
$random_position = rand(0,strlen($string)-1);
$chars = "qwertyuiopasdfghjklzxcvbnmQWERTYUIOPASDFGHJKLZXCVBNM0123456789-_";
$random_char = $chars[rand(0,strlen($chars)-1)];
$newString = substr($string,0,$random_position).$random_char.substr($string,$random_position);
echo $newString;