title: Use while loop to increment values in an array, untill all values are => 100
body: <p>So this is one of the exercises in the book <a href="https://media.readthedocs.org/pdf/howtothink/latest/howtothink.pdf" rel="nofollow noreferrer">how to think like a cs, python3</a>, at page 138:
  Use a mask to multiply all values below 100 in the following list by 2:</p>
  <p><code>a = np.array([230, 10, 284, 39, 76])</code></p>
  <p>Repeat this until all values are above 100. (Not manually, but by looping)
  Then, select all values between 150 &lt; a &lt; 200.</p>
  <p><strong>So I tried to do this:</strong></p>
  <pre><code>while a.all() &lt;= 100:
      a[a &lt; 100] *= 2
  
  print(a[150 &lt; a &lt; 200])
  </code></pre>
  <p>It doesn't exit the loop, even though It stops multiplying after it reaches [230 160 284 156 152].</p>
  <p>Sorry if this is a question that has been asked before, but I couldn't find an answer anywhere...</p>