title: Merge two numpy arrays
body: <p>I am trying to merge two arrays with the same number of arguments.</p>
  <p>Input:</p>
  <pre><code>first = [[650001.88, 300442.2,   18.73,  0.575,  650002.094, 300441.668, 18.775],
           [650001.96, 300443.4,   18.7,   0.65,   650002.571, 300443.182, 18.745],
           [650002.95, 300442.54,  18.82,  0.473,  650003.056, 300442.085, 18.745]]
  
  second = [[1],
            [2],
            [3]]
  </code></pre>
  <p>My expected output:</p>
  <pre><code>final = [[650001.88, 300442.2,   18.73,  0.575,  650002.094, 300441.668, 18.775, 1],
           [650001.96, 300443.4,   18.7,   0.65,   650002.571, 300443.182, 18.745, 2],
           [650002.95, 300442.54,  18.82,  0.473,  650003.056, 300442.085, 18.745, 3]]
  </code></pre>
  <p>To do that I create simple loop:</p>
  <pre><code>for i in first:
          for j in second:
              final += np.append(j, i)
  </code></pre>
  <p>I got i filling that i missing something. First of all my loop i extremely slow. Secondly my data is quite have i got more than 2 mlns rows to loop. So I tried to find faster way for example with this code:</p>
  <pre><code>final = [np.append(i, second[0]) for i in first] 
  </code></pre>
  <p>It working far more faster than previous loop but its appending only first value of second array.
  Can you help me?</p>