bmesh_deform_layer.py

"""
This simple example of Blender Python script prints membership of verticies in vertex groups and weights. It uses deform layer.
"""

import bpy
import bmesh

obj = bpy.context.object

# Get the active mesh
me = obj.data

# Get a BMesh representation
bm = bmesh.new()   # create an empty BMesh
bm.from_mesh(me)   # fill it in from a Mesh

group_index = obj.vertex_groups.active_index
dvert_lay = bm.verts.layers.deform.active

if dvert_lay is not None:
    for vert in bm.verts:
        dvert = vert[dvert_lay]
        print(vert.index, ' vertex groups: ', dvert.items())
        # Print value of active layer
        print(dvert[group_index])

bmesh_vertex_groups.py

"""
This simple example of Blender Python script prints memberships of verticies in vertex groups.
"""

import bpy
import bmesh

# get active mesh
obj = bpy.context.object
me = obj.data

# Enter edit mode
return_to_object_mode = False
if obj.mode == 'OBJECT':
    bpy.ops.object.mode_set(mode='EDIT')
    return_to_object_mode = True

# get bMesh representation
bm = bmesh.from_edit_mesh(me)

# iterate through the vertex group 
for group in obj.vertex_groups:

    # set current vertex group to active
    bpy.ops.object.vertex_group_set_active(group=str(group.name))

    # select the active vertex group
    bpy.ops.object.vertex_group_select()

    # get all currently selected verts
    vertices = [v for v in bm.verts if v.select]

    # vertex iteration
    for vertex in vertices:
        print("Vertex ", vertex.index, " is in ", group.name)       

    # deselect the current vertex group             
    bpy.ops.object.vertex_group_deselect()

if return_to_object_mode is True:
    bpy.ops.object.mode_set(mode='OBJECT')