On 12/26/2018 9:53 PM, jf...@ms4.hinet.net wrote:
I saw the code below at stackoverflow. I have a little idea about the scope of
a class, and list comprehension and generator expressions, but still can't
figure out why Z4 works and Z5 not. Can someone explain it? (in a
not-too-complicated way:-)
class Foo():
XS = [15, 15, 15, 15]
Z4 = sum(val for val in XS)
The iterable passed in to the comprehension is XS.
try:
Z5 = sum(XS[i] for i in range(len(XS)))
The iterable passed in to the comprehension function is range(len(XS)).
XS is a class name, not a global or outer function local name, hence
invisible to the inner function.
except NameError:
Z5 = None
print(Foo.Z4, Foo.Z5)
60 None
--Jach
--
Terry Jan Reedy
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