title: How to convert float notation to power of 10 scientific notation in Python?
body: <p>In <code>Python</code>, I have values given by <code>0.000001,0.00001,0.0001,....,1.0</code> stored in <code>my_Array</code> (<code>np.array</code>). 
  For each of these values I need to label a curve in a plot and store it in the legend as <code>val = 10e-6</code> instead of <code>val = 0.000001</code>.
  The second version is automatically stored if I use (for the <code>i</code>'th value):</p>
  
  <pre><code>matplolib.pyplot.plot(...., label = 'val = ' + str(my_Array[i]))
  </code></pre>
  
  <p>Is there a function converting the float notation to the scientific power of 10 notation?</p>