title: Changing hostname in a url
body: <p>I am trying to use python to change the hostname in a url, and have been playing around with the urlparse module for a while now without finding a satisfactory solution. As an example, consider the url:</p>
  
  <p><a href="https://www.google.dk:80/barbaz">https://www.google.dk:80/barbaz</a></p>
  
  <p>I would like to replace "www.google.dk" with e.g. "www.foo.dk", so I get the following url:</p>
  
  <p><a href="https://www.foo.dk:80/barbaz">https://www.foo.dk:80/barbaz</a>. </p>
  
  <p>So the part I want to replace is what urlparse.urlsplit refers to as hostname. I had hoped that the result of urlsplit would let me make changes, but the resulting type ParseResult doesn't allow me to. If nothing else I can of course reconstruct the new url by appending all the parts together with +, but this would leave me with some quite ugly code with a lot of conditionals to get "://" and ":" in the correct places.</p>