Command works in python console but not in script editor

Question

I am trying a simple script to change a material attribute (Emission Level).

The command works in the python console but not as a script run from the text editor. No error messages.

Script below, delays put in for tracing purposes.

#set frame to 0
bpy.data.scenes["Scene"].frame_current = 0

#set segment g on
print("setting segment g on")

bpy.data.materials["segment g"].node_tree.nodes["Principled BSDF"].inputs[20].default_value = 10.0

print("wait 5")
time.sleep(5)

#set segment g off
print("setting segment g off")
bpy.data.materials["segment g"].node_tree.nodes["Principled BSDF"].inputs[20].default_value = 0.0

print("wait 5")
time.sleep(5)
print("finished")

Answer 1

There probably are error messages of some kind in the system console. Get to the system console by, on Linux, running blender from CLI, or on Windows, clicking Window -> Toggle System Console, and then look for errors there.

One thing I notice is that you never imported bpy, which happens automatically in the Blender Python console but not when running scripts. Try adding that.

Answer 2

insert

import bpy
import time

as your first 2 lines. Then it works. As TheLabCat already stated right, in the console some libraries are imported by default which doesn't happen if you run your script.