How to determine if there is an object on the scene?

Question

Unity

How to determine if there is an object on the scene?
That is, to determine whether he is on stage or not?
Many thanks to whoever helps!

Answer 1

What is an "object"? And how is your object different from another.
So the wagon options:
- some kind of flag in its eweik / destroy
- some kind of flag in that it instantiates / destroys it (or even better a collection)
- search by script
- search by tag / layer
- search by name (buee)