php - Preg_match and substr together -

i have string need test see if characters after [0] character (the first) numbers or not.

so example :

c [0]

i need check if remaining characters numbers meaning after c :

12345678

making string c12345678

this have tried :

 elseif(substr($str, 1, preg_match("/^[0-9]/", $str) === false))      {        $this -> set_message('is_valid_student_id', 'must have 8 digits 0 - 9');        return false;      } 

the first character character last 8 numeric.

thanks

edit 1 :

so doing guys told me not giving me expected outcome...

elseif (preg_match("/^\c\d{8}$/i", $str) === false) // lower case cc + 8 digits      {        $this -> set_message('is_valid_student_id', 'must have 8 digits 0 - 9');        return false;      } 

is not returning false if type in letter after first letter [c or c]

how non-regex solution?

demo

$student_id = "c123b5678";  if(ctype_alpha($student_id[0])){     if(ctype_digit(substr($student_id,1,strlen($student_id) - 1))){        echo 'valid';     }     else{        echo 'invalid';     }  } else { echo 'invalid starting character'; } // echoes invalid 

edit: pointed out cryode, is_numeric() far broad application. allow strings c1e5 pass valid... using ctype_digit() fixes issue. if desired, add check strlen() well.