How to change text in animation for multiple objects in a Python loop

Question

I have about 300 text objects, of which the texts need to change during the animation (numbers in a graph). I came across this Python method using applicatoin handlers: Keyframe on text body in Python?

My problem is: it works if I do this for one object at a time, but not when i use a for loop:

for p in pricelist:
    pname = p[0]
    plist = p[1:]
        
    text = bpy.data.objects[pname]
    print(pname, text.data.body)
        
    def update(self):
        text = bpy.data.objects[pname]
        frame = bpy.context.scene.frame_current
        text.data.body = f'{plist[scene.frame_current]}'
    
    def register():
        bpy.app.handlers.frame_change_post.append(update)

    def unregister():
        bpy.app.handlers.frame_change_post.remove(update)

    register()

(with pricelist being a list of lists, every row contains the object name (first item) and after that, for every frame a value in a string).

When I run it, nothing happens. Sometimes, I have not figured out when this occurs, I get the error "ReferenceError: StructRNA of type Object has been removed" in the terminal over and over again as the animation plays.

Why does this not work, and how do I get the texts of 300 objects to change in the animation in one go?

Thanks in advance for your thoughts!

Answer 1

It looks like the update function is overridden in forloop in blender, but making a wrapper fixes that.

import bpy

# add 2 text object
bpy.ops.object.text_add(location=(0,0,0))
bpy.ops.object.text_add(location=(0,2,0))
#

list2 = [
    ["Text", [f"Cube: frame={r}"  for r in range(500)]],
    ["Text.001", [f"Cube.001: frame={r}"  for r in range(500)]]
]

objs = bpy.data.objects

def wrap(name, l):
    def update(self):
        print("update start", name)
        frame = bpy.context.scene.frame_current
        objs[name].data.body = f'{l[frame]}'
    return update

for name, l in list2:
    fx = wrap(name, l)
    
    def register():
        print("reg", name)
        bpy.app.handlers.frame_change_post.append(fx)
        print("len", len(bpy.app.handlers.frame_change_post))

    register()

Here is an example that doesn't work

import bpy

# add 2 text object
bpy.ops.object.text_add(location=(0,0,0))
bpy.ops.object.text_add(location=(0,2,0))
#

list2 = [
    ["Text", [f"Cube: frame={r}"  for r in range(500)]],
    ["Text.001", [f"Cube.001: frame={r}"  for r in range(500)]]
]

objs = bpy.data.objects

for name, l in list2:
    def update(self):
        print("update start", name)
        frame = bpy.context.scene.frame_current
        objs[name].data.body = f'{l[frame]}'

    def register():
        print("reg", name)
        bpy.app.handlers.frame_change_post.append(update)
        print("len", len(bpy.app.handlers.frame_change_post))

    register()