title: Python String "Modifiers"
body: <p>What are these "modifiers" called on the front of a python string?  I don't understand what these are used for.  Also, since I don't know what they are called, I don't know what to search for to learn about them (or the others that may be available if any).</p>
  
  <p>In this example what does the "u" represent on the front of the string in the return?</p>
  
  <pre><code> def __unicode__(self):
          return u'title: %s, text: %s, created:%s, tags: %s' % (self.title, self.text, self.created, self.tags)
  </code></pre>
  
  <p>In this django URL example, what does the "r" represent?</p>
  
  <pre><code>urlpatterns = patterns('',
      (r'^admin/',include(admin.site.urls)),
  )
  </code></pre>
  
  <p>I'm learning python and django and I see these in examples, but do not have an explanation of what they represent.</p>