SCRIPT TO DELETE ALL OBJECTS IN 3D WINDOW

Script to delete all objects in 3D window:

import bpy


bpy.ops.object.select_all(action='TOGGLE')
bpy.ops.object.delete(use_global=False)

BPY SCRIPT TO ADD A CUBE AND A MATERIAL TO IT

The following script can be used  to add  a cube and a material to it:

 

import bpy

bpy.ops.mesh.primitive_cube_add(location=(0,0,0))
obj_matl=bpy.data.materials.new("obj_clr")
obj_matl.diffuse_color=(1,0,0)
mesh=bpy.context.object.data
mesh.materials.append(obj_matl)