title: For Loop in Python 3.0
body: <p>So, I have a really weird question that has kinda always bugged me.  In this example:</p>
  
  <pre><code>patterns = [ 'this', 'that' ]
  text = 'Does this text match the pattern?'
  
  for pattern in patterns:
      print('Looking for "%s" in "%s" -&gt;' % (pattern, text))
  </code></pre>
  
  <p>So this is just a example, but what I'm wondering, is in the for loop, pattern was never declared, and I know that Python is a dynamic language so you dont have to declare variables, but how does python like know what it means? I've seen this alot with for loops and alot of the time it just seems like people put whatever they want in that part of the for loop, and I really don't get it. Does it matter what you put there?</p>