How to kill(or update) track-to/aim constraint for camera with Python API

Question

I can track objects with camera constraints. I want to update object which we aimed(tracking new objects). So, I tried to update target object of the constraint but it does not work. Now, I am trying to kill camera constraint but camera should be remain so I would set it to track another object. The camera constraint code shown below.

cam_data = bpy.data.cameras.new('camera')
cam = bpy.data.objects.new('camera', cam_data)
bpy.context.collection.objects.link(cam)
cons = cam.constraints.new(type='TRACK_TO')
cons.target = track_object
scene.camera = cam

Answer 1

Your code fragment is missing two things:

1. How you set the scene variable. I'll assume you wanted the active scene and use

scene = bpy.context.scene

2. How you set the track_object variable. I'll assume you wanted the active object and use

track_object = bpy.context.active_object

With those two changes, your code looks like

import bpy

track_object = bpy.context.active_object
scene = bpy.context.scene

cam_data = bpy.data.cameras.new('camera')
cam = bpy.data.objects.new('camera', cam_data)
bpy.context.collection.objects.link(cam)
cons = cam.constraints.new(type='TRACK_TO')
cons.target = track_object
scene.camera = cam

and when I run it it creates a camera with a Track To constraint set to point at the active object in the scene I created.

When I later execute

cons.target = bpy.data.objects["Suzanne"]

and I have a Monkey in the scene, the Track-To target changes to the Monkey.

So your problem seems to be that you haven't set track_object to the object you want as the target.

EDIT:

Here is a Blend file with a cube and a monkey. I've modified the code to use the cube rather than the active object as the first target of the track to, but you can double check my work. It's a 3.0.1 file, but should work just fine in any Blender version since 2.8