title: concatenating arrays in python like matlab without knowing the size of the output array
body: <p>I am trying to concatenate arrays in python similar to matlab </p>
  
  <pre><code>array1= zeros(3,500);
  array2=ones(3,700);
  array=[array1, array2];
  </code></pre>
  
  <p>I did the following in python:</p>
  
  <pre><code>array1=np.zeros((3,500))
  array2=np.ones((3,700))
  array=numpy.concatenate((array1, array2), axis=2)
  </code></pre>
  
  <p>however this gives me different results when i access try to  "array[0,:]"
   is there a way in python to put arrays in one array similar to matlab. </p>
  
  <p>Thank you</p>