how to set a axis constant and plot rest in a matrix?

  python, python-2.7, python-3.x

I am new to Python and I am stuck. I have a 2D matrix with [40×3] dimensions. I want to set its 3rd column as constant (let’s say 1) and then I want to plot its first 2 columns. Next time I want to set the second column constant and plot rest 2 (first, third) and vice versa. Would anyone be so kind to help me with this issue?

Source: Python-3x Questions