title: Python Pandas Accessing values from second index in multi-indexed dataframe
body: <p>I am not really sure how multi indexing works, so I maybe simply be trying to do the wrong things here. If I have a dataframe with</p>
  
  <pre><code>        Value
  A  B         
  1  1    5.67
  1  2    6.87
  1  3    7.23
  2  1    8.67
  2  2    9.87
  2  3    10.23
  </code></pre>
  
  <p>If I want to access the elements where B=2, how would I do that? df.ix[2] gives me the A=2. To get a particular value it seems df.ix[(1,2)] but that is the purpose of the B index if you can't access it directly?</p>