title: Numpy: How to stack arrays in columns?
body: <p>Let's say that I have n numpy arrays of the same length. I would like to now create a numpy matrix, sucht that each column of the matrix is one of the numpy arrays. How can I achieve this? Now I'm doing this in a loop and it produces the wrong results. </p>
  
  <p>Note: I have to be able to stack them next to each other one by one iteratively.</p>
  
  <p>my code looks like assume that get_array is a function that returns a certain array based on its argument. I don't know until after the loop, how many columns that I'm going to have.</p>
  
  <pre><code>matrix = np.empty((n_rows,))
  for item in sorted_arrays:
      array = get_array(item)
      matrix = np.vstack((matrix,array))
  </code></pre>
  
  <p>any help would be appreciated</p>