title: Edit an array value using another array with the positions that should change
body: <p>It's the end of my first month coding with python and I'm struggling with a piece of code that seemed simpler in my mind.</p>
  
  <p>I'm trying to edit array values based on the positions given by another array generated by <code>np.argwhere</code>. For example:</p>
  
  <pre><code>a = np.arange(6).reshape(2,3)
  
  b = np.argwhere(a&gt;3)
  
  c = ([7,8,9],[10,11,12])
  </code></pre>
  
  <p>Now I want to change the values in <code>c</code> that are in the same position as the values that are greater than 3 in the array <code>a</code>.</p>
  
  <p>I'm trying to avoid a for loop because of the size of the real data I am working on.</p>
  
  <p>Thanks in advance!</p>