class Some(object):
    tokens = [ ... list of strings ... ]
    untokenized = [tokens.index(a) for a in [... some other list of strings ...]]
    ... etc ...
some = Some()

This works fine with Python2.7. However python3 says:

Traceback (most recent call last):
File "./test.py", line 17, in <module>
    class Some(object):
File "./test.py", line 42, in Some
    untokenized = [tokens.index(a) for a in [... some other list of strings ...]]
File "./test.py", line 42, in <listcomp>
    untokenized = [tokens.index(a) for a in [... some other list of strings ...]]
NameError: global name 'tokens' is not defined

Though I can work around the problem, I really would like to know what's difference here between Python2 and Python3. I've read python 2->3 changes documents, but I was not able to identify any description which is related to my problem. Also 2to3 tool does not complain anything in my code.

By the way, though I can't recall the situation now, but I had something similar with python2 only too (I haven't even tried this with 3), I thought this should work (within a class):

def some_method(self):
    return {a: eval("self." + a) for a in dir(self) if not a.startswith("_")}

However it causes python2 saying: NameError: name 'self' is not defined I haven't tried this with python3 yet, but for example this works:

[eval("self." + a) for a in dir(self) if not a.startswith("_")]

If I change the relevant part of the previous example to this one (ok the example itself is a bit stupid, but it shows my problem at least). Now I am very curious, why self seems not to be defined for this first example but it is for the second? It seems with dicts, I have similar prob

python python-3.x
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