title: How to find the exact intersection of a curve (as np.array) with y==0?
body: <p>How can I get from a plot in Python an exact value on <em>y</em> - axis? I have two arrays <code>vertical_data</code> and <code>gradient(temperature_data)</code> and I plotted them as:</p>
  
  <pre><code>plt.plot(gradient(temperature_data),vertical_data)
  plt.show()
  </code></pre>
  
  <p>Plot shown here:</p>
  
  <p><a href="https://i.stack.imgur.com/hs8Mt.png" rel="noreferrer"><img src="https://i.stack.imgur.com/hs8Mt.png" alt="plot"></a></p>
  
  <p>I need the zero value but it is not exactly zero, it's a float. </p>