title: Issue converting Data frame datatype from object to float64
body: <p>I need to convert the datatype of y_test from object to float64. I first converted into an array of strings ( <strong>In[54]</strong> ) and then to an array of floating point numbers (<strong>Inputs [83] &amp; [85]</strong>)  but it is not added to the y_test data frame.</p>
  <p>y_test feature CO(ppm) is still displayed as <em>object</em> datatype ( <strong>Out[90]</strong> ).</p>
  <p><strong>Can someone please help me understand how to accomplish this? Thank you.</strong></p>
  <p><a href="https://i.stack.imgur.com/SUaFa.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/SUaFa.png" alt="enter image description here" /></a></p>