title: Convert a 1D array to a 2D array in numpy
body: <p>I want to convert a 1-dimensional array into a 2-dimensional array by specifying the number of columns in the 2D array. Something that would work like this:</p>
  
  <pre><code>&gt; import numpy as np
  &gt; A = np.array([1,2,3,4,5,6])
  &gt; B = vec2matrix(A,ncol=2)
  &gt; B
  array([[1, 2],
         [3, 4],
         [5, 6]])
  </code></pre>
  
  <p>Does numpy have a function that works like my made-up function "vec2matrix"? (I understand that you can index a 1D array like a 2D array, but that isn't an option in the code I have - I need to make this conversion.)</p>