def make_drop_list(columns):
    """The canvas exports will have some annoying fields
        These should be added to the droppable list
        If there are columns with a common initial string (e.g., 1.0, 1.0.1, ...) just
        add the common part
    """
    droppable = ['1.', 'Unnamed']
    to_drop = ['n correct', 'n incorrect']
    for c in columns:
        try:
            if float(c):
                to_drop.append(c)
        except ValueError:
            for d in droppable:
                if c[:len(d)] == d:
                    to_drop.append(c)
    return to_drop
