title: Numpy how to iterate over columns of array?
body: <p>Suppose I have and m x n array.  I want to pass each column of this array to a function to perform some operation on the entire column.  How do I iterate over the columns of the array?</p>
  
  <p>For example, I have a 4 x 3 array like</p>
  
  <pre><code>1  99 2
  2  14 5
  3  12 7
  4  43 1
  
  for column in array:
    some_function(column)
  </code></pre>
  
  <p>where column would be "1,2,3,4" in the first iteration, "99,14,12,43" in the second, and "2,5,7,1" in the third.</p>