Tuples and immutability
ian.g.kelly at gmail.com
Sun Mar 2 13:32:35 CET 2014
On Sat, Mar 1, 2014 at 7:04 PM, Eric Jacoboni <eric.jacoboni at gmail.com> wrote:
> In fact, i think i'm gonna forget += on lists :)
Well, do what you want, but I think you're taking the wrong lesson
from this. Don't forget about using += on lists. Instead, forget
about using assignments, augmented or otherwise, on tuple elements.
Would you expect this to work?
tup = (1, 2, 3)
tup += 42
I'm guessing probably not. So I have a hard time understanding why it
should be expected to work any differently when the tuple element
happens to be a list. The fact that the list is actually modified I
think is a distraction from the main point: the error indicates that
something illegal happened, not that nothing has changed. Assignments
just are not allowed on tuple elements, and it doesn't matter what
type they happen to be.
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