title: Spark dataframe cast decimal(33,16) to float issue
body: <p>I have numeric(33,16) in the database. It values are line <code>25.55</code>, <code>26.4343</code> etc.
  When I am converting this to spark dataframe, it is getting converted to decimal and the values are converted to <code>25.5500000000000000</code> and <code>26.4343000000000000</code>. It is adding zero till the 16 places after decimal.</p>
  
  <p>I need to cast these as float. When I cast this as float, it is changing as <code>25.5499999999999999999</code> etc.</p>
  
  <p>How can I fix this?</p>