title: Regex validation pattern only allows one character
body: <p>I'm trying to make functions for validating usernames, emails, and passwords and my regex isn't working. My regex for usernames is <code>^[a-zA-Z0-9 _-]$</code> and when I put anything through that should work it always returns false.</p>
  
  <p>As I understand it, the <code>^</code> and <code>$</code> at the beginning and the end means that it makes sure the entire string matches this regular expression, the <code>a-z</code> and <code>A-Z</code> allows all letters, <code>0-9</code> allows all numbers, and the last three characters (the space, underscore, and dash) allow the respective characters.</p>
  
  <p>Why is my regular expression not evaluating properly?</p>