title: Pandas - get first n-rows based on percentage
body: <p>I have a dataframe i want to pop certain number of records, instead on number I want to pass as a percentage value. </p>
  
  <p>for example,</p>
  
  <p><code>df.head(n=10)</code></p>
  
  <p>Pops out first 10 records from data set. I want a small change instead of 10 records i want to pop <strong>first</strong> 5% of record from my data set.
  How to do this in pandas.</p>
  
  <p>I'm looking for a code like this,</p>
  
  <p><code>df.head(frac=0.05)</code></p>
  
  <p>Is there any simple way to get this? </p>