title: How to use python pandas groupby or .DataFrameGroupBy objects to create unique list of combinations
body: <p>Is there a more efficient way to use pandas groupby or pandas.core.groupby.DataFrameGroupBy object to create a unique list, series or dataframe, where I want unique combinations of 2 of N columns. E.g., if I have columns: Date, Name, Item Purchased and I just want to know unique Name and Date combination this works fine:  </p>
  
  <pre><code>y = x.groupby(['Date','Name']).count()
  y = y.reset_index()[['Date', 'Name']]
  </code></pre>
  
  <p>but I feel like there should be a cleaner way using </p>
  
  <pre><code>y = x.groupby(['Date','Name'])
  </code></pre>
  
  <p>but y.index gives me an error, although y.keys works. This actually leads me to ask the general question as what are pandas.core.groupby.DataFrameGroupBy objects convenient for?</p>
  
  <p>Thanks!</p>