Question

Is there a way in python\pydev to see and access instances of a certain class while debugging?
For instance, if I define SomeClass and various modules in a single python interpreter script instantiate this class, is there a way to see how many such instances exist in the interpreter and to access their attributes in a central fashion, without coercing the code to hold references to them from a single location (such as the module where the class is defined)?

Answer 1

You could find all such objects using gc.get_objects():

For example, if you define Foo class in module othermod.py:

class Foo(object):
    pass

f2 = Foo()

then you can count all instances of Foo in script script.py like this:

import gc
import othermod

f = othermod.Foo()

objs = gc.get_objects()
# print(len(objs))
# 3519

print(len([obj for obj in objs if isinstance(obj,othermod.Foo)]))
# 2

Caveat: gc.get_objects does not track instances of atomic types (like int or str), but it sounds like that is not the kind of object you want to track.