title: add column Numpy array python
body: <p>I am very new to python and am very familiar with R, but my question is very simple using Numpy Arrays:</p>
  <p>Observe:</p>
  <p>I have one array X of dimension (100,2) of floating point type and I want to add a 3rd column, preferably into a new Numpy array of dimension (100,3) such that the 3rd column = col(1)^2 for every row in array of X.</p>
  <p>My understanding is Numpy arrays are generally of fixed dimension so I'm OK with creating a new array of dim 100x3, I just don't know how to do so using Numpy arrays.</p>
  <p>Thanks!</p>