title: Filter dataframe based on columns without name values
body: <p>I have a dataframe which I need to filter if the value of two columns for each row is bigger than two specific numbers. Also, it's important that I don't know anything of the dataframe except that those columns are the numbers -2 and -3</p>
  
  <p>For example, we have <code>dataframe = pd.DataFrame(data=[[1,2,3,4],[5,6,7,8],[1,2,-3,4],[5,-6,7,8]])</code>. Imagine that we need to filter it if the -2 and -3 columns are bigger than 0. In this case, we'll return only the first two rows.</p>
  
  <p>I've tried it using <code>return dataframe[(dataframe[:, -3] &gt;= 0) and (dataframe[:, -2] &gt;= 0)]</code>, but it gives me the following error: <code>TypeError: unhashable type: 'slice'</code>.</p>