title: Python 3.x: Merge two dictionaries with same keys and values being array
body: <p>Python version: 3.x</p>
  
  <p>I have two dictionaries with same keys and the values are arrays. Most of the questions I saw here, for the required purpose, have only one value for each key. What I want is to merge those two dictionaries with values as joined array. Maybe below would clear:</p>
  
  <p>What I've:</p>
  
  <pre><code>d1 = {(1, "Autumn"): np.array([2.5, 4.5, 7.5, 9.5]), (1, "Spring"): np.array([10.5, 11.7, 12.3, 15.0])}
  d2 = {(1, "Autumn"): np.array([10.2, 13.3, 15.7, 18.8]), (1, "Spring"): np.array([15.6, 20, 23, 27])}
  </code></pre>
  
  <p>I've tried:</p>
  
  <pre><code>d3 = {**d1, **d2}
  </code></pre>
  
  <p>What I want:</p>
  
  <pre><code>d3 = {(1, "Autumn"): np.array([2.5, 4.5, 7.5, 9.5, 10.2, 13.3, 15.7, 18.8]), (1, "Spring"): np.array([10.5, 11.7, 12.3, 15.0, 15.6, 20, 23, 27])}
  </code></pre>
  
  <p>Am I missing something here? Please help!</p>
  
  <p>P.S: I've looked at <a href="https://stackoverflow.com/questions/38987/how-to-merge-two-dictionaries-in-a-single-expression">How to merge two dictionaries in a single expression?</a>.</p>