title: How to get the coefficients returned from interp1d in scipy?
body: <p>Using  <a href="https://docs.scipy.org/doc/scipy/reference/generated/scipy.interpolate.interp1d.html" rel="nofollow noreferrer">iterp1d</a> from scipy you can fit a cubic to some data. But how do you get the coefficients of the cubic polynomial that you have just fitted?</p>
  
  <p>As a trivial example:</p>
  
  <pre><code>from scipy.interpolate import interp1d
  x = [1, 2, 3.5, 4] 
  y = [2, 3, 4, 5] 
  f = interp1d(x,y, kind='cubic')
  </code></pre>