title: Python: Pandas - Separate a Dataframe based on a column value
body: <p>Suppose I have a dataframe as shown below:</p>
  
  <pre><code>in:
  mydata = [{'subid' : 'B14-111', 'age': 75, 'fdg':1.78},
            {'subid' : 'B14-112', 'age': 22, 'fdg':1.56},]
  df = pd.DataFrame(mydata)
  
  out:
         age   fdg    subid
      0   75  1.78  B14-111
      1   22  1.56  B14-112
  </code></pre>
  
  <p>I want to separe the dataframe to two different dataframes based on the "age" column, as shown below:</p>
  
  <pre><code>out:
     df1: 
             age   fdg    subid
          0   75  1.78  B14-111
  
     df2:
  
             age   fdg    subid
          1   22  1.56  B14-112
  </code></pre>
  
  <p>How can I achieve this?</p>