title: PHP: need explanation using [a-zA-Z0-9]
body: <p>I am new to PHP (not programming overall), and having problems with this simple line of code. I want to check whether some input field has been filled as anysymbolornumber@anysymbolornumber just for checking whether correct email was typed. I don't get any error, but the whole check system doesn't work. Here is my code and thanks!</p>
  
  <pre><code>  if ($email = "[a-zA-Z0-9]@[a-zA-Z0-9]")
  {
  </code></pre>