PHP - detect whitespace between strings

Question

How would I go about detecting whitespace within a string? For example, I have a name string like:

\"Jane Doe\"

Keep in mind that I don\'t want to trim or re

Answer 1

// returns no. of matches if $str has nothing but alphabets,digits and spaces.
function is_alnumspace($str){
  return preg_match('/^[a-z0-9 ]+$/i',$str);
}