title: How to truncate a series/column of a data frame with single operation
body: <p>There are operations to round or floor or ceiling a column/series of a dataframe but how can one specify the precision for a column and truncate the rest of the values?</p>
  
  <pre><code>df = pd.DataFrame({"a": (1.21233123, 1.2412304498), 'b':(2.11296876, 2.09870989)})
  </code></pre>
  
  <p>Given this simple data frame, lets say I want to truncate column a and column b to 3 precision without rounding, I simply want to remove the rest of the precision.</p>
  
  <pre><code> df = pd.DataFrame({"a": (1.212, 1.241), 'b':(2.112, 2.098)})
  </code></pre>
  
  <p>This would be a result df, there should be a column operation that can be executed but it seems that you can only specify precision for rounding.</p>