Hide Blender's grid floor programmatically When a new install of Blender opens, there is a camera, a light source, a cube and a matrix of vectors on the x,y 16x16 plane.

As I do not know what this is called, I cannot search for it to switch it off or change its values.  I've checked Neal Hirsig's grand reference, and gone through the User Preferences, but cannot find what I'm looking for.

What is this reference vector matrix called?  How can I modify it?  I want to toggle it into/out from my 3D ViewPort Editor Window.

EDIT: OK we know it is now called the grid floor, but I need to toggle it programmatically and didn't ask for that at first.

bpy.types.SpaceView3D.show_floor = False


does not appear to work in code.
To show or hide the grid floor you must first find the 3D view space, then use the space's show_floor porperty:

import bpy

def find_3dview_space():
    # Find 3D_View window and its scren space
    area = None
    for a in bpy.data.window_managers[0].windows[0].screen.areas:
        if a.type == 'VIEW_3D':
            area = a
            break

    if area:
        space = area.spaces[0]
    else:
        space = bpy.context.space_data

    return space

space = find_3dview_space()
space.show_floor = False


What you tried to do is to access the SpaceView3D type, which is the class of the 3D view space object. You cannot access methods directly from the class, but rather need to find the object instantiating that class as specified above.