title: Get list of pandas dataframe columns based on data type
body: <p>If I have a dataframe with the following columns:</p>
  <pre><code>1. NAME                                     object
  2. On_Time                                      object
  3. On_Budget                                    object
  4. %actual_hr                                  float64
  5. Baseline Start Date                  datetime64[ns]
  6. Forecast Start Date                  datetime64[ns] 
  </code></pre>
  <p>I would like to be able to say: for this dataframe, <strong>give me a list of the columns which are of type 'object' or of type 'datetime'</strong>?</p>
  <p>I have a function which converts numbers ('float64') to two decimal places, and I would like to use this list of dataframe columns, of a particular type, and run it through this function to convert them all to 2dp.</p>
  <p>Maybe something like:</p>
  <pre><code>For c in col_list: if c.dtype = &quot;Something&quot;
  list[]
  List.append(c)?
  </code></pre>