syntax glitch with +=
staschuk at telusplanet.net
Fri Feb 21 01:40:50 CET 2003
Quoth Irmen de Jong:
> David Eppstein wrote:
> > If L and M are lists, L += M is the same as L.extend(M), right?
> > Nope:
> You're getting
> UnboundLocalError: local variable 'l' referenced before assignment
> right? This error has nothing to do with a presumed difference
> between extend and +=, in this case.
But that is exactly the difference. Using += triggers the
"assigned-to variables are local" rule, while using .extend() does
Steven Taschuk "The world will end if you get this wrong."
staschuk at telusplanet.net (Brian Kernighan and Lorrinda Cherry,
"Typesetting Mathematics -- User's Guide")
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