How to put similar named objects into collection in python?

Question

I wrote a script that can detect similar objects based on the selected objects but can't put them in a collection named after selected objects.

It's not working.

import bpy 

selected_objects = bpy.context.selected_objects

for selected_object in selected_objects:
    name = selected_object.name
    collections = bpy.data.collections.new(name)
    bpy.context.scene.collection.children.link(collections)
    bpy.ops.object.select_pattern(pattern=f"*{name}*")
    objs = bpy.context.selected_objects
    coll = bpy.data.collections[name]

    for obj in objs:
        cols = obj.users_collection
        coll.objects.link(obj)
        for col in cols:
        col.objects.unlink(obj)

I want from:

To:

Answer 1

I would do the same in python that I could do in the UI, which is to use Select Pattern, and then move these selected items to a Collection.

In python:

bpy.ops.object.select_all( action='DESELECT' ) # Deselect all objects
bpy.ops.object.select_pattern(pattern="Sphere*")

# if collection Sphere does not yet exist:
bpy.ops.object.move_to_collection( collection_index=0, is_new=True, new_collection_name='Sphere' ) # new collection
# else if collection Sphere does exist:
bpy.ops.object.move_to_collection( collection_index=2 ) # need collection index

Answer 2

Here is another script where Collection names are used, with link and unlink:

bpy.ops.object.select_all( action='DESELECT' ) # Deselect all objects
bpy.ops.object.select_pattern(pattern="Sphere*")
objs = bpy.context.selected_objects

sphColl = bpy.data.collections['Spheres']

for obj in objs:
    print(obj)
    cols = obj.users_collection # ptr to current collection
    sphColl.objects.link(obj) # link into 'Spheres' collection
    print(cols)
    for col in cols:
        col.objects.unlink( obj ) # unline from original collection

Answer 3

Object to collection by name.

Similarly to https://blender.stackexchange.com/a/166446/15543 can do this with API methods.

• Sort all objects in scene by name (could change this to selected objects if desired)

• Get the name up to the ".", eg for "Cube.022" this is "Cube", and all objects that start with this name

• Move to collection of same name. Make a new collection and link to scene collection if need be. This will ensure can run this again and again and again without moving "Cube" to collection named "Cube.001" then "Cube.002" etc

• Repeat until all objects moved.

• Optionally remove any collections left with zero objects.

Test script.

import bpy

context = bpy.context
scene = context.scene
obs = scene.objects[:]
obs.sort(key=lambda o: o.name)

def move(name, obs):
    # unlink from old collections
    for o in obs:
        for c in o.users_collection:
            c.objects.unlink(o)
    # make a new collection and link to it
    coll = bpy.data.collections.get(name)
    if not coll:
        coll = bpy.data.collections.new(name)
        scene.collection.children.link(coll)
    for o in obs:
        coll.objects.link(o)
    

while obs:
    name = obs[0].name.split(".")[0] 
    x = [o for o in obs if o.name.startswith(name)]
    move(name, x)
    obs = obs[len(x):]
    
# remove any now empty collections

empty_colls = [c for c in bpy.data.collections if not len(c.all_objects)]

while empty_colls:
    bpy.data.collections.remove(empty_colls.pop())