title: Should I use raw string by default?
body: <p>I know raw string, like <code>r'hello world'</code>, prevents escaping.</p>
  
  <p>Is it a good practice to always prepend the r symbol even if the string doesn't have any escaping sequences?</p>
  
  <p>Say my exception needs some string literal explanation, I need to connect to a website whose url is a string literal. They don't have backslash. Are there any performance differences between raw string and regular string?</p>