Php check exist have how many random int numbers in string

I have rand function like;

$mynumbers = rand(1111,9999);
echo $mynumbers;

Example output is 3582

and I have another strings

$mystring = "Ja9Js78I4PhXiF464R6s7ov8IUF";  (Have 1 number, must be turn 1 (only 8 have))
$mystring2 = "Ja3Js73I4P1X5iF564R8s2ov8IUF"; (Have 4 numbers, must be turn 4 (have all of them))

And i want to know this with function ;

$mystring is have, how many numbers ? inside $mynumbers and how many time ? passed when this process ? How can i do it ?